Author: chogan@directresearch.com

Post #1642: Hallelujah! The report.

 

Background

As I sit down to do my legally-mandated Cyber Monday shopping, I’d like to talk about a somewhat-less-commercial aspect of Christmas.

Last night, my wife and I attended the 51st annual Messiah sing-along at Clarendon United Methodist Church. For those of you unfamiliar with this tradition, Messiah is a baroque oratorio about the birth and death of Christ.  The words are straight out of the King James Bible (ca. 1611).  The music is straight out of the early 18th century (ca. 1741).

Despite these handicaps, the Christmas portion of it is still widely performed at this time of year (ca. 2022). The phrase used last night was “it’s been running longer than Cats”.

Talented soloists do the hard parts, while the audience serves as the chorus.  The audience ranges from excellent singers, to people like me (I can usually make it through the notes), to folks that are mostly lost, most of the time.  But it’s all good.  If you can’t sing the 16th notes, no problem.  Just sing what you can.

In a typical year, in the Washington DC area, there are easily a half-dozen Messiah sing-alongs to choose from.  I suspect the same is true for most cities across the U.S.

I’d like to say that it’s a way for us to kick off the holiday season on a more spiritual note.  But, really, for us, it’s more about the music.

My wife and I agree that, should we ever have access to a time machine, our first act would be to go back in time and kill Katherine Kennecott Davis, thus saving the Western world from untold billions of mind-numbing parum-pa-pum-pums.

The report

We attended this sing-along for several years ending in 2019.  Every pre-COVID-year, the church was more-or-less packed.  To the point where we’d come early to make sure we could get a parking place.  There was a lot of gray hair in the audience.  And a large portion of the audience had been attending that Clarendon UMC Messiah sing-along for years, if not decades.

Choral singing is such a risk for spread of COVID that we hesitated to return to it.  Even after calculating the odds (I crudely figured a 1-in-300 chance of picking up a COVID infection there), it still felt a little iffy.  I had to wonder if we were just being wimps about this.  Seems like almost everything is back to almost normal,despite continued new COVID-19 cases, hospitalizations, and deaths that would be considered high during any other part of the pandemic.

We’re going back to this one, in the era of endemic COVID, because they require masks.  Near as I can tell, none of the other sing-alongs in the area do that.  I briefly went over why choral singing is such a risk for spread of COVID-19 in my last post on this (Post #1638).  So the masks seem prudent, to me.

Turns out, we are far from alone in hesitating to return to mass choral singing.

I would guess that the church was less than half-full last night.  In addition, the church had set up a broadcast for those who wished to attend virtually.

Moreover, the composition of the audience had changed.  By eye, there was less gray hair.  By show of hands, more than half were there for the very first time.  Only a handful of persons in the audience were multi-decade veterans of this event.

In hindsight, I interpret that as showing that many of the church’s aging, veteran singers decided not to attend in person.  Which makes a lot of sense, if you think about who is most at risk.

But is nevertheless a shame.  It suggests to me that if the current new-case levels really are the “endemic” or long-term level of COVID in the population, then this event will never fully recover from the pandemic.  It’s an event that largely catered to an elderly audience, but now carries an inherently high risk of COVID-19 infection.  That’s just not a winning combination in the era of endemic COVID.

Whether or not the newcomers will eventually repopulate that sing-along, it’s far too soon to tell.  I give Clarendon UMC credit for soldiering on.  I dropped a wad of cash in the collection basket on my way out, because it can’t be cheap to hire a small orchestra plus soloists.  But unless the level of COVID in circulation falls greatly, I suspect that this will only survive in its current, greatly reduced, form.

As for the other sing-alongs in the area, my wife is uncomfortable attending unless masks are required.  The science says that singing generates as much aerosols as coughing.  In this era, do you really want to stand in a big room full of people continuously coughing, and none of them wearing masks?

Ah, yeah, I think that’s where we draw the line.  At least at the current level of COVID-19 incidence.

The issue of mandatory masks for mass choral events cuts both ways.  We wish some other Messiah sing-alongs would follow Clarendon’s lead on the issue of masks.  But, I guess, it’s a question of whether the organizers of those events figure they’d lose more audience by requiring it, than not.  Maybe with a younger audience, no mandatory masks is the attendance-maximizing decision.  Last night, though, I’m pretty sure that masks were key to the modest level of attendance that was achieved.

Post #1641: Of Freon and Schrader Valves

 

Let me get to the punch line first, and tell the story second.

Yesterday, I found out that:

  1.  I own about $5,000 worth of R-22 refrigerant, a.k.a., Freon.  That’s at full retail, the price I’d have to pay currently to replace it.
  2. That $5K worth of refrigerant is held in place by a less-than-reliable $1 device that was invented in the late 1800s.

As an economist, I goggle at the mismatch.

But there appears to be nothing I can do about it.  Except to wait for the inevitable leak.

Now I’ll tell the story.  And try go get up to speed on modern refrigerant options.  And try to plan ahead.

My world and welcome to it.

My house came with an exceptionally quirky HVAC system.

The key elements are a pair of ground-source heat pumps.  That sounds pretty eco-friendly and high-tech, right?

As actually implemented, my home HVAC is a Rube Goldberg machine.  There’s a mile of plastic pipe buried in the back yard. Two pumps circulate water through that mile-long loop, terminating at two commercial (not home) AC compressors.  These grumble away in the basement, feeding refrigerant lines running to air handlers — the things that actually blow the hot or cold air around the house.  Those air handlers were clearly part of an earlier system, and to reach the one in the attic, the installers ran about 100′ of refrigerant lines outside, up the side of the house, and over top of the roof.  The whole mess is controlled by a mix of wired and wireless thermostats of dubious reliability.  These, in turn, interface with the 65-year-old three-zone baseboard hot water heat via a high-tech high-efficiency gas furnace and electronic interface, that actually turns the hot water baseboards on and off via valves than run on melted wax.  (That’s not sarcasm, that’s a Taco (pr. Tay-co) valve.)

I mean, what could possibly go wrong?

In any case, we fired up the heat pumps this past weekend, only to find that one of the two heat pumps wasn’t.  Pumping heat, that is.

A service call later, and the diagnosis is that the unit is drastically low on refrigerant. 

Normally, that’s not much of an issue.  Find the leak, fix it, and refill the system.

But in this case, it’s a problem.  That’s because the bozos who installed those heat pumps less than 20 years ago cheaped out and installed units that use R-22 refrigerant, also known as Freon.  Of ozone destruction fame. That can no longer be made in the U.S. or imported into the U.S. 

(At the time they installed these, it was already well known that Freon was on its way out.  When I replaced the AC in my prior house, years before, I opted for the newer “Puron” (R410-A) refrigerant.  Buying a new R-22 unit at that time would have been foolish.  But now I own two of them.)

Normally, that’s not much of an issue either.  There are now drop-in replacement refrigerants like R-421A.  These don’t destroy the ozone layer, and in most cases you can simply vacuum out the R-22, replace with R-421A (or similar), and get on with your life.  (They have a huge global warming potential, though, as discussed below.)

But in this case, it’s a problem.  Apparently those replacements won’t work in every system.  My HVAC guy assures me that mine is one such.  Maybe the 100′ long refrigerant lines have something to do with that.  Maybe it’s the fact that these are oddball commercial units, not home units.

So in my case, the options were to fix the leak and top up the leaking unit with R-22, or throw it away and get a new one.  Which, owing to the unique setup, is almost certainly going to cost a mint.  Assuming my HVAC guy is giving me the straight story.

So I had my HVAC guy repair the leak and top up the system.  Which is when I found out that this company now charges more than $300 a pound for R-22.  I expected it to be expensive — that’s been in the works since 2010, when the decision was made to phase it out in the U.S.   Which means my replacement cost for the 14+ pounds of R-22 in my two units is somewhere around $5000.

(But I didn’t expect it to cost me more than $300 a pound, but it was a decision that I made on the fly.  I now see that the wholesale price of R-22 is around $40 a pound.  As shown below.   So my HVAC guy apparently took a roughly 800 percent markup.  Because, hey, my system wasn’t going to run without that additional R-22.  So they got me.  But this definitely means I’m looking for a new HVAC firm.  And I’m also wondering whether I got the straight scoop regarding whether or not drop-in replacement refrigerants will work.)

 

 

And what caused the leak, for which I had to purchase about $1500 worth of R-22?  That was due to a faulty Schrader valve.  Which is a roughly 70 cent part, using a design patented in 1893.

And that’s just the way it is.  The valves that made sense when they were holding in the (then) $1 a pound Freon are now are all that stands between the atmosphere and my precious antique R-22.

Looking ahead.

Given the dollars involved, I probably ought to think through what my next steps are.  As opposed to panic-purchasing something the next time there’s a problem.

There are a lot of considerations.

Source:  US EPA

First, with no new production or import allowed in the U.S., at the current price, it’s a pretty good bet that R-22 is now a zero-sum game.  That is, everything currently residing in appliances will get reclaimed and re-used, until it all eventually leaks into the atmosphere.

(In theory, per the EPA, you can ship your R-22 off to have it destroyed at a certified destruction facility.  Or you can plan on storing it safely, indefinitely.  But I don’t see that happening if you can re-sell it to your customers at $300+ a pound.

This means there is no environmentally benign way to get rid of the R-22 that came with my house.  If I opt for new equipment, the HVAC techs will, by law, recover (pump out) all the R-22  in the current system.  But surely they’ll sell that to be reclaimed and re-used.  Which means that it will be used in somebody else’s leaky system.  And one way or the other, it’s going to end up in the atmosphere.

I should mention here that in addition to R-22’s destruction of the ozone layer, all these refrigerants — even the ozone-benign ones — have a horrifically high global warming potential (GWP).  R-22 isn’t the worst, but it’s bad enough, with a 100-year GWP of 1850 (reference).  Or, in other words, a pound of that stuff has as much impact as 1850 pounds of C02.  My little R-22 leak had as much global warming impact as releasing about four tons of C02.  That’s about the same global warming impact as an entire year’s worth of electricity use, in my house.

I think that gives me my first and most obvious decision point:  As long as my current heat pumps don’t leak, I should make every effort to keep them running.  Even though the equipment is old, it’s still a reasonably efficient heating and cooling plant because it’s a ground-source system.  I don’t think any marginal efficiency improvements from new equipment could plausibly offset the GWP from the earlier-than-necessary release of my 14 pounds of R-22.

The fact that I own this R-22 is nothing for me to feel guilty about.  I’m not the one who installed the R-22 heat pumps.  But now, I’m the custodian of it.  It’s on me to address any leaks, to try to keep this crap bottled up for as long as possible.

Conversely, as soon as a unit develops an irreparable leak, I should decommission it.  With one caveat.  My HVAC guy actually gave me the option of just refilling the system, and not bothering to find the leak.  With a slow leak, plausibly I could have kept this running for years on maybe a pound of R-22 per year.  But if I could not fix the leak, it would be better that the R-22 go into somebody else’s system, with the chance that it doesn’t leak, than to keep it in a known leaky system.

(And so, that’s the first benefit of thinking this through.  Because, had this occurred in some sort of emergency situation, such as a deep cold snap, I’d probably have opted to keep the system running at all costs.  Now I have my head screwed on straight regarding the environmentally sound(er) thing to do.)

The caveat is that the systems you can get today all use refrigerants with high global warming potential.  So much so that refrigerants that were cutting-edge replacements for R-22 twenty years ago are themselves now being phased out.  Puron (R410-A), for example, has a GWP of more than 2000.  It came on the market in 1996, and it’s slated to be phased out sometime in the 2030s.

So the caveat boils down to this:  If we’re only a year or two away from new units that use a truly benign refrigerant (no ozone destruction, minimal GWP), it might make sense to limp along for that year or two, rather than install new equipment with soon-to-be-outdated refrigerant.

Right now, as I read it, the world of low-GWP refrigerants is in flux.  For heat pumps, Carrier now makes a large commercial ground-source unit using R-1234ze, with claimed GWP of less than 1 (reference).  Looks like some other manufacturers are jumping on that bandwagon.  So, plausibly, if that trend continues and they enter the home heating and cooling market, by the time I have to replace these old R-22 ground-source heat pumps, I ought to have a fairly efficient and environmentally benign alternative.

In the meantime.

Meanwhile, I remain appalled that the same century-old tech that keeps my car tires inflated is all that stands between my precious R-22 and the outside world.  When my HVAC guy comes back for a routine maintenance visit in the spring, I’ll be grilling him about options for making sure I never get another Schrader valve leak on these systems.  Maybe I can have him replace those prophylactically (there are tools for replacing them with out losing the R-22).  Maybe it’s a question of putting gas-tight caps over them.

One way or the other, there has to be a more secure way to keep this particular genie in the bottle.  The valves that made sense 20 years ago seem ridiculously out of place for a gas that’s going for hundreds of dollars a pound.

Post #1640: Humidifiers, first fill of the season.

 

Why humidify?

Among the many things I wish I’d never had to learn, but did, because of COVID, is the term “mucociliary clearance”.  And, hand-in-hand with that, I now understand that the standard advice to “drink plenty of fluids” when you have a cold has nothing to do with your kidneys.  That’s actually for the health of your lungs.

Your entire upper respiratory tract is lined with mucous membranes, and in addition much of the surface is lined with little hairs (cilia).  Mucous itself has substances that fight pathogens, and the cilia sweep the mucous toward the top of your throat, where you (ahem) eliminate that mucous in some fashion.

This is the primary mechanism by which your lungs protect and clean themselves.  Of anything that lands on the surface of the lungs.  Mucous traps things before they can actually get to your lung cells.  And then your lungs continuously sweep the mucous lining up toward your throat, where it gets disposed of.

And so, the whole point of “drink plenty of fluids” is to keep your mucous loose, per WebMD.

To today’s point, dry air inhibits mucociliary clearance, and humid air increases it.  (Also referenced halfway through this review article.)  And it’s not exactly rocket science to understand it:  Dry air dries out your mucous.  That slows down the rate of transport.  And so your entire upper respiratory tract functions less well at cleaning itself, and protecting itself from pathogens.

That’s why four out of five HVAC engineers agree:  Keep your indoor relative humidity between 40% and 60%.  That recommendation is based, in part, on studies like this one, of mice and flu, literally out of the American Society of Heating, Refrigeration, and Air conditioning Engineers (ASHRAE) handbook:

Source:  ASHRAE.

See Post #894 for other studies, including ones using guinea pigs, and ones effectively using school children as guinea pigs.

With this latest bout of cold weather, the relative humidity in my house has finally fallen to 40%.  So I’m firing up my first humidifier today. 

After having tried many different types of humidifiers over the years, I’ve decided that I hate them all (Post #895).  Noisy, dusty, stinky, and/or expensive. Take your pick.  I have grudgingly settled on a pad-type humidifier with removable tanks as the least-hassle approach to maintaining indoor humidity.

I’ll be toting 2-gallon jugs of water for the next few months, keeping that filled.

All that, just to keep up my mucociliary clearance.

Post #1639, COVID-19 still 13/day, maybe an East/West split?

 

And, as of today, the U.S. is at 13 new COVID-19 cases / 100K / day, more-or-less the same as it has been for the past three weeks.  There’s a visible upward trend for most of the Mountain states.  And maybe the current pattern of increases and decreases mirrors the weather we were having a couple of weeks ago, with a very warm East and a fairly cold West.  (Recall that the seven-day-moving average reported today reflects infections that were occurring about two weeks ago, on average.)

Finally, data reporting has gotten so sketchy that I had to write a new algorithm to gap-fill the periods over which states fail to report.  Nobody ever cares about the statistical methods, but I figured I should state it.  In most cases, the new case counts with the new method will differ only slightly from what I was showing under the old method.

 

Continue reading Post #1639, COVID-19 still 13/day, maybe an East/West split?

Post G22-064: Judgement Day, the Seedy Edition.

 

Or Judgment, depending on which style guide you follow.

When I started trying new varieties of plants in my little backyard garden, I did not quite grasp one obvious consequence:  At some point, you have to thin down your seed collection. 

Left to its own devices, my shoebox of seed packets exhibits reverse Darwinism: Survival of the un-fittest.  It’s not merely that I end up with far too many packets of seeds.  It’s that the long-term survivors are the duds — the ones I didn’t want to plant again.  By contrast, plants with desirable traits are removed from my shoebox gene pool, because I planted the seeds and grew them.

It’s a nice metaphor for much of the junk in my life.  The shirts I wear every day eventually wear out.  The ill-fitting and the ugly remain until I haul them off to the thrift shop.  The low-fat, low-salt cottage cheese slowly expires at the back of the fridge.  But somehow my pantry has never held a bag of potato chips beyond its expiration date.

Why is this seed pack a loser?  Let me count the ways.

Above: The starting point.  It’s not quite as chaotic as it looks, because I have them sorted into categories.

1)  I just ain’t gonna grow that vegetable any more.

Here, the varieties themselves are blameless.  It’s mostly that nobody wanted to eat them, even if I grew them well.  Or, in a few cases, that, plus they seemed to be more trouble than they were worth.

Maybe I’ll try to give these away.  There’s nothing wrong with the seeds.

  • Radishes
  • Turnips
  • Kale
  • Swiss Chard
  • Ground cherry

2) I ain’t gonna grow that variety any more.

Some of these just didn’t grow well.  Some didn’t taste like much.  And, to be clear, I’m tossing some not because they are intrinsically bad but because I could use the same space for better varieties.

2.1) Tomatoes

 

These all grew, but were disappointing for some reason.  Some, I couldn’t tell when they were ripe.  Others lacked taste.  Some had poor yields, possibly due to operator error.  But mostly, they aren’t themselves bad, it’s just that there were better varieties for my garden conditions.

2.2)  Squash

At the end of the day, I’m sticking with a handful of tried-and-true varieties of winter and summer squash.  As with the tomatoes above, the ones pictured here  just didn’t do as well as other varieties that I planted.

From now on, I’ll do a couple of varieties of winter squash (Dickenson pumpkin, Waltham butternut squash), a couple of varieties of summer squash (prolific yellow straightneck, black beauty zucchini), and call it a day.

2.3 Cucumbers.

I’m giving up on cucumbers for the time being.  Cucumber beetles are now endemic to my garden.  I’m not willing to use the strong toxins it would take to get rid of them, and none of the varieties above is sufficiently resistant to bacterial wilt, spread by cucumber beetles.  In addition, my attempt at growing parthenocarpic cukes under insect netting failed.  I’m giving it a rest next year.

Conclusion

With that thinning, everything now fits in one plastic shoebox.  In theory, I ought to vacuum-seal these seeds, so they’d last longer.  In practice, I tend to use them up before they start failing to germinate.

This has been an odd post, in that all I talked about is the stuff that didn’t work.  But every once in a while, you have to clean house.  By its nature, that has to focus on the duds.

Post #1638: Hallelujah! Or maybe not. Messiah sing-alongs in the era of endemic COVID.

 

Background

In the runup to Christmas, my wife and I like to attend sing-alongs of Handel’s Messiah.  That’s the one with the Hallelujah Chorus.   I posted about this in December 2019, Post #496.

Or, rather, liked.  Past tense.  That was pre-COVID.

As we learned the hard way, both here and abroad, getting together with a bunch of people and singing is probably the single easiest way to spread COVID-19.  In the U.S., the first such choral super-spreader event was the Mount Vernon, Washington choir practice, which left dozens ill and several dead.  Abroad, many countries saw similar incidents, such as this superspreader event at a church choir in Berlin.

There’s no mystery here.  COVID-19 is spread by aerosols, and singing produces as much aerosol as coughing.  From the standpoint of spreading an aerosol-borne disease, standing in the middle of a choir practice is equivalent to standing in a room full of people who are continuously coughing.

It just sounds a lot better.

Most churches all figured this out, at some point, and pretty much all mainstream U.S. churches banned singing in church during the height of the pandemic (see Post #708).  But that was only after a number of church-related super-spreader events (see Post #679).

Along with that, of course, many (but far from all) Messiah sing-alongs were cancelled for one or more years.

They’re back

A typical example of the adaptation of Messiah to COVID is the long-standing event at Clarendon United Methodist Church.  We attended for years, and it was always one of the best in the area.  The last pre-COVID year was the 2019, when they held their 48th annual sing-along.   In 2020, risks were high enough that they cancelled the in-person service, and instead offered up a retrospective on (what would have been) their 49th Messiah sing-along (reference).  In 2021, they held an in-person service for their 50th annual event, but required masks and proof of vaccination or recent negative PCR test (reference).  Finally, this year, in 2022, they are holding their 51st sing along, with masks required (reference).

Others that we have consistently attended in the past are being offered this year, but with no requirement for masks.  To pick an example, the Reston Chorale always manages to put on a very nice rendition of Messiah.  The ads for the 2022 sing-along make no mention of any precautions (reference).

Near as I can tell, Clarendon UMC is the outlier for requiring any precautions at all.  No others that I have found in my area make any mention of a mask requirement.

So, what are the odds?

Clarendon UMC looks like it holds about 500 people.  Using the same calculation that I’ve used in the past, with our current rate of roughly 10 new cases per day per 100K population, the odds that at least one person in that crowd has an active COVID-19 infection is 36% (calculation not shown).

This should probably be moderated somewhat by this being an elderly and fairly upscale crowd.  So the true odds may be somewhat smaller than that.

Then come all the unknowables.

First, being in the same church as someone with an active case is not the same as getting infected.  Mainly because of distance, but also because my wife and I have both recently had the bivalent booster shot, so our immunity should still be pretty good.

Second, it’s not clear what the impact of the masking requirement will be.  It cuts down the risks, for sure.  And I’ll be wearing a 3M unvented N95, appropriately fitted.  But there’s no telling what the average singer will be wearing.  Or how they will be wearing it.

Finally, there’s the evidence from last year’s events.  I cannot find even a single mention of an outbreak of COVID being traced back to a Messiah sing-along.  I don’t know whether that’s because it didn’t happen, because it wasn’t traced, or because it just didn’t make the news.

If I had to roll it all up into one big explicit guess, between a) the size of the church, b) our recent booster shot, c) the age and high educational attainment of the audience, and d) N95 respirators, I’d have to guess at least a 100-fold reduction in the odds of actually acquiring a COVID-19 infection at this event. Relative to that 36% chance that somebody attending the event with have an active case of COVID.

Or maybe a one-in-300 chance of getting infected. Fully acknowledging the guesswork that went into that.  But, you know, it’s better to make a decision with some number in mind, no matter how hazily derived, then just go with a gut feeling.

And to me, right now, for something I’m going to do once a year, that number doesn’t look too awful.

So, YOLO.  And I ain’t getting any younger.  After talking it over with my wife, maybe it’s time to get out our Messiah scores and start get up to speed on our parts.

Hallelujah.

Post #1637, COVID-19, still 13/100k, Mountain states, and a couple of calculations.

 

It now definitely looks like an uptrend in new COVID-19 cases in the Mountain states.  And maybe the Midwest.  And maybe the start of an uptick in a couple of other regions.  And yet, there’s no uptrend in Canada, or in alpine Europe.  And, as of today, the U.S. remains at 13 new COVID-19 cases / 100K / day, same as it was two weeks ago.  But with an upward trend now.

Separately, I’m redoing the math to check whether or not I can dismiss the steady 3300 daily new COVID-19 hospitalizations as consisting mainly of people hospitalized with COVID, as opposed to those being hospitalized for COVID.  And the answer is no, I can’t.  The numbers just don’t work out.  Near as I can tell, we’re still seeing 3300 a day hospitalized for COVID, and 350 a day dying from COVID.  That means that COVID-19 remains far more serious than seasonal flu. Continue reading Post #1637, COVID-19, still 13/100k, Mountain states, and a couple of calculations.

Post #1636: Countertop water filtration.

 

This is my overview of simple (no-plumbing) water filtration systems currently on the market.  As with many of my posts, I’m writing this up to make sure I understand the topic.  I doubt anyone will read the detail.

To cut to the chase, after 20 years, we’re abandoning our standard Brita water filter in favor of the upgraded version, the Brita Elite.  The new Brita filter fits the old pitchers, but appears to do a much better job at filtration.

This, while I continue to look over our options for a more sophisticated filtration system.

In brief:

Continue reading Post #1636: Countertop water filtration.

Post #1635: First frost

 

Source:  Analysis of historical weather data from NOAA.

Stealth frost

It looks like we’re going to have a few nights with freezing temperatures this week, here in Vienna, VA.

I’ve been doing a few chores in and around the garden to get ready for that.  The most important of which was moving a large potted lime tree into the garage.  Even a touch of frost and that would likely die back to the ground.  I’ve also drained all the water barrels, and I’m bringing hose timers and other frost-sensitive objects inside.

This means it’s also time to redo my prior analysis of trends in first frost.  It’s been unseasonably warm in the East, so it would be no surprise if this year’s first frost were a bit later than usual.

But when I actually looked at the data, I got a surprise:  Dulles Airport (my standard for this frost analysis) recorded a frost about three weeks ago, on October 21.  I missed that, and clearly we didn’t get a frost in Vienna, based on (e.g.) the fact that my okra plants are still alive.

That said, on average, first frost in my area is now about 20 days later than it was in the 1960s.  As you can probably see from the graph, virtually all that change has been in this century.  That couple-of-weeks shift in the first frost date appears to be a fairly widespread phenomenon (per this reference).

That’s consistent with the continued northward shift of the USDA hardiness zones.  They update those every so often, using more recent historical weather (i.e.) climate data.  With the most recent up date (2012, using the 30 years of weather ending 2010), most of the zone boundaries slid north, compared to the prior map (using the 30 years ending in 1990).  Apparently, the average rate of travel of the hardiness zone boundaries is reported at 13 miles (north) per decade (per that same reference).  That varies widely, as zone boundaries at the coast shift more slowly, due to the moderating effects of ocean temperatures.

In any case, it will be sometime around 2040 before Vienna, VA makes it into Zone 8 — or Zone 8 makes it to Vienna — take your pick.

Source:  NOAA, via the New York Times 

So I guess it’s still a bit early to expect climate change to save me from these frost-related chores.  But give it enough time, and we our descendants our descendants, if any, will have no problem growing palm trees around here.

As was true at last year’s first frost date (Post G21-057), indoor relative humidity remains high.  That said, I’m keeping an eye on it, and when it drops below 40%, I’ll start running my humidifiers.  I summarized why that’s important for prevention of respiratory infections in Post #894.

Source:  American Society of Heating, Refrigerating and Air-Conditioning Engineers