This is weird. This represents a change over a mere ten year period.My zone hasn't changed (still 6b), but USDA states the lowest T has gone up 5F (-10,-5) to (-5,0).
Last winter we had -10F for a week. This winter we had -20F for a week.
What I find strange is that the interval from the last assessment is small, only 10 years. And yet in two of those we broke records in the opposite direction of that reported. Note that USDA is not reporting the average, but the coldest temps likely to be encountered.
Even if the winter is trending warmer, I would think two record breaking cold winters in a ten year span would change my local data downwards, not up.
This has affected me. For three years I have tried planting chicago hardy figs. For three years we've had chicago like winters and the figs didn't make it (chicago hardy needs a couple of mild winters to withstand chicago temps).
What do I know? YMMV
4/18/2026
at
7:13:28 PM
"Hardiness zones in this map are based on the average annual extreme minimum temperature during a 30-year period in the past" https://planthardiness.ars.usda.gov/pages/how-to-use-the-map... (the page also reflects this in one of the sections).So it doesn't matter if it was -20 F all year or for 1 day, either counts as 1 value of -20 F out of 30 annual measurements to be averaged. 2 record breaking cold winters out of 11 wouldn't necessarily imply much with over 1/3 of the averaged data being replaced (it'd depend more on the 11 years replaced than the 2 new extremes), and that should show in the graph of the exact yearly values used towards the middle.
I do sort of wish it opened with the deeper explanation of what the data is first and then got to showing you the values second. Giving someone numbers, having them try to interpret them, and then telling them what it was the numbers were actually trying to measure is a recipe for creating confusion.
by zamadatix
4/18/2026
at
7:26:23 PM
[dead]
by nmbrskeptix
4/18/2026
at
11:27:30 PM
>This represents a change over a mere ten year period.For our, city dwellers, perception changes over 10 years may be unnoticeable, while over longer periods - that is how about 4 decades look in my hometown in Russia (one though need to be at least 50 years old to feel the changes happening over 40 years :)
https://news.ycombinator.com/item?id=18948971
Where is, naturally, even a 1/4th of such changes is noticeable and meaningful for industrial agriculture.
by trhway
4/19/2026
at
1:18:29 AM
Not noticeable??2016, the day after election day. I took a picture out the front door, there was a "dead" (leaves dead, roots will come back next year) yam plant in it--completely normal, they were always dead by November. Next time we elected him there were still some green leaves into January. Last winter they did not winter kill at all.
And this year we did the Fletcher Canyon hike 6 weeks early. Should have needed snowshoes, in reality microspikes were desirable for the last few feet. Even last year you would have been laughed at for suggesting it in March, this year there was one woman in the group wearing not much more than a bikini. And most of the high summits have been reported clear weeks ago.
by LorenPechtel