[HN Gopher] The USDA's gardening zones have shifted. (Interactiv...
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       The USDA's gardening zones have shifted. (Interactive app and map)
       (2024)
        
       Author : nuke-web3
       Score  : 63 points
       Date   : 2026-04-18 16:31 UTC (6 hours ago)
        
 (HTM) web link (apps.npr.org)
 (TXT) w3m dump (apps.npr.org)
        
       | starkparker wrote:
       | (2024), via https://www.npr.org/2024/05/13/1250855166/big-news-
       | for-garde...
       | 
       | Further context from 2023:
       | https://www.npr.org/2023/11/17/1213600629/-it-feels-like-im-...
        
         | altairprime wrote:
         | (2 years ago, 218 comments)
         | https://news.ycombinator.com/item?id=40342578
        
       | nmbrskeptix wrote:
       | 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
        
         | zamadatix wrote:
         | "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.
        
       | comrade1234 wrote:
       | I have property in NW WI and I planted 5 paw paw trees. I had
       | heard that there's a paw paw in Madison so I had hope. I bought
       | them from a tree farm in MI that said they had discovered a cold-
       | resistant paw paw.
       | 
       | One of them survived over five years now! It's still really small
       | but I think it'll make it. Even if it grows up there's two
       | problems - the summer may not be long enough for it to produce
       | fruit. And two, they reproduce by sexual reproduction. The only
       | way it will produce fruit is if there's another paw paw in the
       | vicinity.
       | 
       | I wanted to plant another batch of trees but when I went to the
       | website of the tree farm there was an announcement that they
       | retired - that they ran the farm for 50 years and it was time to
       | retire. So no more cold-hardy paw paw.
       | 
       | I live in Zurich which is about the same latitude as NW WI and
       | there's a bunch of paw paw trees at a tennis club near my house.
       | They produce copious amounts of fruit. And there's constantly
       | random new paw paw trees sprouting up. But the weather is much
       | nicer here.
       | 
       | Maybe some day the weather in NW WI will be mild enough to match
       | Zurich.
        
         | lanyard-textile wrote:
         | May be worth reaching out still :)
         | 
         | The commercial operation is retired but they may still help an
         | enthusiast.
        
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       (page generated 2026-04-18 23:01 UTC)