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New USDA Hardiness Zone Map

Posted by digit ID/WA (My Page) on
Wed, Jan 25, 12 at 12:01

After using the same one for over 20 years, the USDA has unveiled their new map. Instead of data from 1974 to 1986, this includes winter weather temperatures from 1976 to 2005:

Plant Hardiness Zones

You may notice some changes to your zone designation. The site is much clearer, you can do a zip code look-up that's USDA official and all you need to do is click on your state to get an up-close view !


Follow-Up Postings:

RE: New USDA Hardiness Zone Map

  • Posted by pcan 7a UT (My Page) on
    Wed, Jan 25, 12 at 13:03

Ha! I spent all weekend going researching temps back 40 years and discovered I was a 7a. Most zone maps showed me as a 5 or 6. Now this new one shows me as a 7a.

I shoulda waited a weekend to do all that work lol.

RE: New USDA Hardiness Zone Map

I'll tell you what, Pcan -- I'd trust your research much sooner than I'd trust a broad-brush map or any zipcode look-up!

If I use the zip code, it shows 6. The map seems to indicate either 6a or 6b but it was only 2 winters ago that the thermometer showed an official -18F and that is nearly a zone 4. . .

Some of you may remember a thread by me back during some very warm winters (this current one may count with them) when I was saying that this must be a zone 6 now. We've had several winter mornings with double digitS' below zero since I was willing to change my zone. The Arbor Day Foundation had me convinced for a year or 2 but the weather has been -20F a number of times since I moved here, many years ago.

That I'm outliving the trees is just NOT an argument!

Steve digits

RE: New USDA Hardiness Zone Map

Hmm, maybe it's my server or something, but I get stuck in a captcha loop that just keeps wanting me to put in another code. So, I reload the page and go into Colorado by state instead of area by zip, and there is no Broomfield county. Since the county officially came into being in 2001, maybe after the next 20 years when the USDA comes out with their new zones map, this will be a useful tool? Maybe by then, captcha hell will have frozen over... wonder what THAT hardiness zone will be? LOL
(side note: clearly, the problem is that whatever map they have doesn't recognize the Broomfield zip codes, but GEEZ, that's just kinda funny that the USDA is 11 years out. Not that I'm surprised...)

RE: New USDA Hardiness Zone Map

I wonder what the problem is, Mayberrygardener.

I tried zip code 80021 that Wikipedia, at least, tells me is in Broomfield County and it showed: "Zone 6a : -10 to -5 (F)"

The only captcha I had was when I looked 1st for a different zipcode that is up here. I was just curious about what it would say on a neighborhood that should be warmest around.

As I said in my last post, tho'. I am much more willing to accept the zone chart and look at the weather records than to trust a zip look up. I just can't help wondering how they can cover so many neighborhoods, when NOAA only seems to keep records at a limited number of weather stations.


RE: New USDA Hardiness Zone Map

Hey Steve,

I heard about the new USDA map on NPR and was pretty stoked to see its new features, especially the interactive GIS-based map that shows very local detail. I found that, from the link you provided, you have to click the tab for the Interactive Map and then click on your area and zoom in from there. If you got caught in captcha hell, Mayberry, maybe it's that your web browser is set to reject cookies. That usually is the source of problems like that for me.

So, I have now changed my zone to 6b, and that's darn encouraging for me, since I posted my questions about how my new high-altitude home might affect my zone.

I do know, however, that this region has gotten colder than -5 in the past, but the last time was around 1989. Back then, it got down to -18 or something like that.

So, is the USDA map not really trying to tell us the extremes we might expect but rather the *typical* lows?

RE: New USDA Hardiness Zone Map

Typical extremes might be the best way to put it, Steve . . .

On their "about" page, the USDA says: "Hardiness zones are based on the average annual extreme minimum temperature during a 30-year period in the past, not the lowest temperature that has ever occurred in the past or might occur in the future. Gardeners should keep that in mind when selecting plants. . ." (my emphasis).

Yes, it seems like I should have to go back more than 2 years to find a winter when the zone map would have proven to be totally bonkers! I guess age & experience might or might not count for something.

It seems like this, like so many things the gov'ment does, is mostly to benefit industry. This industry being the plant trade . . . push your luck too much and you get to buy new plants! Good for the economy & raises the GDP.

(Good thing, I don't mind seeing dirt in the winter and enjoy growing mostly annuals. ;o)

trapped in February - the 2 a.m. of the year.

RE: New USDA Hardiness Zone Map

Interesting! I've been zone 4 since we bought our land outside of town, but on the new map we're zone 5a (and Cheyenne proper is zone 5b now!)

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