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Last Frost usually January 31 or before First
Frost usually November 30-December 31 |
Sunset Magazine Zone 13 is considered the low desert region of the southwest, it includes Phoenix, Yuma, Palm Springs, Death Valley and a narrow strip running the length of the lower Colorado. The winters are nearly non-existent, with only 15 nights of freezing temperatures ranging from 13°F to 19°F and an average minimum of 37°F. Summers are hot with average highs of 106°F to 108°F. Rainfall varies upon location with virtually none in the Mojave and 14 plus inches in the Sonoran desert. |
| USDA Zones | Fahrenheit | Celsius |
|---|---|---|
| 1 | Below -50 F | Below -45.6 C |
| 2a | -50 to -45 F | -42.8 to -45.5 C |
| 2b | -45 to -40 F | -40.0 to -42.7 C |
| 3a | -40 to -35 F | -37.3 to -39.9 C |
| 3b | -35 to -30 F | -34.5 to -37.2 C |
| 4a | -30 to -25 F | -31.7 to -34.4 C |
| 4b | -25 to -20 F | -28.9 to -31.6 C |
| 5a | -20 to -15 F | -26.2 to -28.8 C |
| 5b | -15 to -10 F | -23.4 to -26.1 C |
| 6a | -10 to -5 F | -20.6 to -23.3 C |
| 6b | -5 to 0 F | -17.8 to -20.5 C |
| 7a | 0 to 5 F | -15.0 to -17.7 C |
| 7b | 5 to 10 F | -12.3 to -14.9 C |
| 8a | 10 to 15 F | -9.5 to -12.2 C |
| 8b | 15 to 20 F | -6.7 to -9.4 C |
| 9a | 20 to 25 F | -3.9 to -6.6 C |
| 9b | 25 to 30 F | -1.2 to -3.8 C |
| 10a | 30 to 35 F | 1.6 to -1.1 C |
| 10b | 35 to 40 F | 4.4 to 1.7 C |
| 11 | above 40 F | above 4.5 C |
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Mountain States Wholesale Nursery webmaster george@mswn.com January 05, 2009 |