Looks like 8A for me then, Lin.

8A for here...

Finally the map agrees with my observations!

I was just about to post this too. It moved me squarely into 8a instead of the edge of it. I guess we all moved about half a zone. Downtown Dallas got moved to 8b.

I saw those little 'pockets' within the general zones, Lynnmarie, and wonder if that's accurate - you can see a bunch of green splotches in zone 8a as well. I guess that accounts for microclimates, but I wonder how much is due to placement (or accuracy) of the measuring equipment.

I like this too, I am in 8A -

As to downtown Dallas (work here) being warmer in zone 8B than the surrounding areas, it's probably due to the downtown area being a concrete jungle with very little green space and the glass buildings may radiate the sun too!

Looks like 8A for me too, but in the 11 years we've been here in Springtown, I have never known the low temps to go below about 20, which would place us in 8B. Not that it matters much anyway. I use the rule of thumb-if it died in the winter, it probably wasn't hardy in this zone. Hi everybody! Can't wait til Spring!!!
Cheryl

Looks like it's 8A for Arlington. Hmmm, if I've always been in zone denial, does this mean I can plant bottlebrush now and expect it to live? Probably not.

Are the possibilities that are suddenly open? Anyone about to try something different....current super-mild winter aside. What does this actually mean for gardeners?

hmmmmm c

Doesn't change much for me here, just the numbers.

I do think my area takes longer to warm up in the spring and longer recovering from the ice and snow.

The temps are accurate but the length of time during those cold spells is longer than most of the rest of zone 8 further south. Which I think has an impact on the plants' survival.

I'll still consider myself zone 7 to be on the safe side, and try to encourage good drainage and mulch well those more iffy tender plants.

Oh, if only the plants could read this and know they have a new zone..............

I would be wary of the new changes. They use a 20 or 25 year cycle of temperatures to derive these zones. The old temperatures took in the decade of the 70's- 80's that were colder and we used it to judge to judge the much milder warmer decades of the 90's - 2010. Well since then we have had a cool down from 2008 on (except this winter) but we are using these warm statistics to base our future predictions. Some predictions have us entering a period of COOLING for the next 30 years due to the Barrycenter Wobble of the sun. The numbers are derrived from past data and not Future forecast. Getting numbers from future forecast is even more problematic since getting computor models and theories to agggree is even more problematic and prone to error. This way is best but just be aware that cycles happen and old numbers might not be the true story today might not be where we are today in a world of cyclical change.

The prior map - 1990 - used only the thirteen ear data from 1974-1986. This new map uses the 30-year period from 1976-2005. The map also attempts to account for coastal and lake effects, as well as elevation differences. I don't see that as a bad thing. This map also splits zones 2-10 into "a" and "b" zones, so we have 20 climatic zones represented.

If you read what Tony Avent has to say on the map and plant hardiness, he raises a lot of good points as to what affects plant winter hardiness, including in part:

: how many times the temperature dropped to the average low, and (as Mel stated) how long it stayed at that temperature.
: acclimation of plants to cold (both at the beginning and end of the cold seasons)
: precipitation - to two extremes - wet winters reducing hardiness of some plants, and heavy/persistent snow cover (not ice) providing increased hardiness

One other point he brought up is heat/summer hardiness of plants - which is more than the number of days above 86. It's more related to night temperatures, humidity, and rain during the hot season.

So, the map is a tool to help me evaluate plant hardiness, but it's not cast in concrete.

Here is a link that might be useful: Tony Avent's article in full