Managing Cover Crops Profitably - Valley Crops Home

Agricultural Research Service, USDA
USDA Plant Hardiness Zone Map
AVERAGE ANNUAL MINIMUM TEMPERATURE
Temperature (˚C) Zone Temperature (˚F)
-45.6 and Below 1 Below -50
-42.8 to -45.5 2a -45 to -50
-40.0 to -42.7 2b -40 to -45
-37.3 to -40.0 3a -35 to -40
-34.5 to -37.2 3b -30 to -35
-31.7 to -34.4 4a -25 to -30
-28.9 to -31.6 4b -20 to -25
-26.2 to -28.8 5a -15 to -20
-23.4 to -26.1 5b -10 to -15
-20.6 to -23.3 6a -5 to -10
-17.8 to -20.5 6b 0 to -5
-15.0 to -17.7 7a 5 to 0
-12.3 to -15.0 7b 10 to 5
-9.5 to -12.2 8a 15 to 10
-6.7 to -9.4 8b 20 to 15
-3.9 to -6.6 9a 25 to 20
-1.2 to -3.8 9b 30 to 25
1.6 to -1.1 10a 35 to 30
4.4 to 1.7 10b 40 to 35
4.5 and Above 11 40 and Above
Source: Bailey, 1994
Ecoregions of the United States
DIVISIONS
The areas within each Division
are Provinces.
1. Tundra
2. Subarctic
3. Warm Continental
4. Hot Continental
5. Subtropical
6. Marine
7. Prairie
8. Mediterranean
9. Tropical/Subtropical Steppe
10.Tropical/Subtropical Desert
11. Temperate Steppe
12.Temperate Desert
13.Savanna
14.Rainforest
Mountains with Altitudinal
Zonation
Source: R.G. Bailey (see p. 162).