A guide to mountain states' gardening climates - Sunset climate zone maps - Brief Article

Sunset, Dec, 2000 by Jim McCausland

* Zone 3B: Mildest intermountain climate

Zone 3B is much like zone 3A, but with slightly milder winter averages (19[degrees] to 29[degrees]F; -7[degrees] to -2[degrees]C) and extremes that usually bottom out between -2[degrees] and -15[degrees]F (-19[degrees] and -26[degrees]C). Summer temperatures here are a bit higher than in zone 3A: They hover mostly in the high 80s and low to mid-90s. Zone 3B offers the longest growing season of all the intermountain climates. Gardeners here count on a growing season of about 180 to 210 frost-free days, with plenty of heat. However, it's one of the smallest zones, found mostly in the warmest parts of eastern Washington's Columbia Basin, in Lewiston, Idaho, and parts of southern Utah, New Mexico, and Arizona.