North and Midwest Hardiness Zone Map
What Is the Map? What Is Your Zone?
The US Department of Agriculture produces a map for gardeners based on the average of low temperature readings taken from weather stations throughout the United States. The idea is to give the garden industry a way to communicate the cold hardiness of landscape plants. That is why the tag of a holly or any other landscape plant often says "hardy to zone __."
Of course, the map also provides vegetable and herb gardeners like you with a rough guide to the extent of cold where you live. Many of our perennial flowers and herbs are hardy as far north as zones 3 or 4. Cool season vegetables, most of which tolerate or even like a little frost, will grow well in Zones 7 and southward in the fall. This is roughly where we distribute transplants to your local garden center at the proper time for planting.
States in the North and Midwest Hardiness Zones:
Iowa, Minnesota, Montana, Nebraska, North Dakota, South Dakota, Wisconsin, Wyoming
Check the color of the section in your area of the map with the color key below.
Zones 2b through 6a represented here.
USDA Hardiness Zones and Average Annual Minimum Temperature Range
| 1 |
Below -50 F |
Below -45.6 C |
Fairbanks, Alaska; Resolute, Northwest Territories (Canada) |
| 2a |
-50 to -45 F |
-42.8 to -45.5 C |
Prudhoe Bay, Alaska; Flin Flon, Manitoba (Canada) |
| 2b |
-45 to -40 F |
-40.0 to -42.7 C |
Unalakleet, Alaska; Pinecreek, Minnesota |
| 3a |
-40 to -35 F |
-37.3 to -39.9 C |
International Falls, Minnesota; St. Michael, Alaska |
| 3b |
-35 to -30 F |
-34.5 to -37.2 C |
Tomahawk, Wisconsin; Sidney, Montana |
| 4a |
-30 to -25 F |
-31.7 to -34.4 C |
Minneapolis/St.Paul, Minnesota; Lewistown, Montana |
| 4b |
-25 to -20 F |
-28.9 to -31.6 C |
Northwood, Iowa; Nebraska |
| 5a |
-20 to -15 F |
-26.2 to -28.8 C |
Des Moines, Iowa; Illinois |
| 5b |
-15 to -10 F |
-23.4 to -26.1 C |
Columbia, Missouri; Mansfield, Pennsylvania |
| 6a |
-10 to -5 F |
-20.6 to -23.3 C |
St. Louis, Missouri; Lebanon, Pennsylvania |
| 6b |
-5 to 0 F |
-17.8 to -20.5 C |
McMinnville, Tennessee; Branson, Missouri |
| 7a |
0 to 5 F |
-15.0 to -17.7 C |
Oklahoma City, Oklahoma; South Boston, Virginia |
| 7b |
5 to 10 F |
-12.3 to -14.9 C |
Little Rock, Arkansas; Griffin, Georgia |
| 8a |
10 to 15 F |
-9.5 to -12.2 C |
Tifton, Georgia; Dallas, Texas |
| 8b |
15 to 20 F |
-6.7 to -9.4 C |
Austin, Texas; Gainesville, Florida |
| 9a |
20 to 25 F |
-3.9 to -6.6 C |
Houston, Texas; St. Augustine, Florida |
| 9b |
25 to 30 F |
-1.2 to -3.8 C |
Brownsville, Texas; Fort Pierce, Florida |
| 10a |
30 to 35 F |
1.6 to -1.1 C |
Naples, Florida; Victorville, California |
| 10b |
35 to 40 F |
4.4 to 1.7 C |
Miami, Florida; Coral Gables, Florida |
| 11 |
above 40 F |
above 4.5 C |
Honolulu, Hawaii; Mazatlan, Mexico |
Map Credits:
The 2003 US National Arboretum "Web Version" of the 1990 USDA Plant Hardiness Zone Map
USDA Miscellaneous Publication No. 1475. Issued January 1990.
Authored by Henry M. Cathey while Director, U.S. National Arboretum
Edited, formatted and prepared for the US National Arboretum web site by Ramon Jordan, March 1998 & Revised March 2001; January 2003
U.S. National Arboretum, Agricultural Research Service, U.S. Department of Agriculture, Washington, DC 20002
Note: This publication is not copyrighted, and permission to reproduce all or any part of it is not required.