New USDA Hardiness Zone Map

[digitS']

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 .

Steve

 

[lesa]

Interesting, Steve- according to that map, I have moved South! Zone 5a...

 

[thistlebloom]

Well I'm supposedly in 6a now, but I'll still but trees and shrubs rated for zone 4, because we do get down to -30 occasionally.
I wonder how much confusion this will add to buying plants. I don't suppose growers will change tags and descriptions right away.

 

[vfem]

Thanks for this Steve! I'm glad to see it updated, and it takes a lot of data over a 'now' period to get closer to what truest for us.

I'm still 7b, boarding 8a within minutes.

So I still chance some zone 8 plants. One year they may just not be able to handle it, but I happen to love trying anyways. Its those FREAK freezes and snows we get once in a blue moon that throw everything off for me.

 

[digitS']

. . . once in a blue moon that throw everything off for me.

Ah Shucks, V . . . There you go mentioning the moon again .

Yeah, I may be in a zone 6 also . . . But, if you look at the map, 'Thistle, you may find that your part of the valley is still in zone 5.

If you want to make a more meaningful determination regardless of a zip code or the map, just use the chart and NOAA's weather information.

We had -18F in the '09/'10 winter, just 2 years ago. I guess that if a tree was supposed to be a zone 6 specimen and only survive to -10, that little cold snap would have killed it :/.

Steve

 

[thistlebloom]

Yeah you're right Steve, I looked again, this time with my reading glasses on, and I'm in zone 5. It won't change my gardening habits, I prefer to err on the side of near catastrophe! At least with the permanent plantings. I don't mind flirting with danger in vegetables and annuals...

Thanks for the info, the changes are a good thing to be aware of.

 

[stano40]

A lot of these changes are due to the magnetic pole moving further towards Russia or are we experiencing an axial shift?

 

[Collector]

This map says I am in 6b now, hope our weather pattern got the memo.

 

[digitS']

The direction a magnetized needle points has to do with the vertical "dip" of the Earth's magnetic field. I could be wrong but I don't see how it would have anything to do with weather.

A change in the axis of the Earth and the Geographic North Pole, would immediately be noted by astronomers! The entire relationship between our horizons and what we see out in space - sun, planets, stars - would be altered.

The effects of pollution on this newer data is another question.

I remember when I was first able to get on the internet and learned a little about the climate studies at Oregon State University. The university had received funding to simply go back and crunch historical weather information including average annual extreme minimum temperatures. Those extreme minimums are what the hardiness zones are based on.

OSU used information anyone can find, if you want to go to every single weather station in the US to get it!

The news from the university program was that this information would be "coming 1-2 years" and would be the basis for new maps on "plant hardiness for all 50 states and possessions." So, when was that announcement made: December, 1998. The information was compiled but the map, apparently tangled in politics, has now taken 13 years to be released!

Steve

 

[grow_my_own]

Wow, according to this, we are in zone 9A now.