One would think that with all the information you see on global warming that it would impact everyone’s local growing situation. In some cases it does and some it doesn’t. It depends on where you live and even in which county you live.
If you look at the data from the University of Missouri annual average temperature, (charts) it looks like we naturally have a wide change in average temperatures.
On the other hand if you look at the data from the Arbor Day Foundation, it shows that while many of the counties show increases in temperature, some do not. It almost looks like there are waves of heat across our country with cooler bands in-between.
What this means for you depends on where you live. Likely you may be able to grow some plants that never would have made it in the past.
New 2012 USDA Hardiness map
The USDA just came out with a new 2012 map which is somewhere in between the Arbor Day Map and the 1990 map.
The USDA says, “The new map is generally one 5-degree Fahrenheit half-zone warmer than the previous map throughout much of the United States. ”
The map is at this link: http://planthardiness.ars.usda.gov
and includes a zip code search function.
It’s interesting to note that if you live in the city of St. Louis, your zone is 6B, but if you live in the county it is 6A
You can download high-quality maps at this link.