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USDA Plant Hardiness Zone Map & Legend
(provided by the United States National Arboretum)
The Chicago area is zone 5a & 5b. It is important to understand that this determines the plants, shrubs, and trees that are most likely to survive our winter weather. When reading plant tags on perennials, shrubs, and trees, verify that the hardiness is listed as 5 or less, if you wish to see them return for future seasons of enjoyment.
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USDA Hardiness Zones and Average Annual Minimum Temperature Range
Zone |
Fahrenheit |
Celsius |
Example Cities |
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 |
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