Ranging from below sea level in the Imperial Valley and Death Valley to 1,100 feet around Phoenix, Zone 13 is a subtropical desert. Average summer high is 107°F (42°C); the world’s second highest temperature—a scorching 134°F (56°C)—was recorded in Death Valley on July 10, 1913. Winters are short and mild,with brief frosts occurring up to 15 nights per year. Average winter minimums range from 36 to 42°F (2 to 6°C), with extreme lows from 27 to 15°F (–3 to –9°C). The gardening year begins in fall for most vegetables and annual flowers, although crops like corn and melons are planted in late winter. Fall-planted crops grow slowly in winter, pick up speed in mid-February, and race through the increasing temperatures of March and April. Spring winds can set back plants, but summer storms cool down gardens, shield plants from the sun, and supply a little extra water.
