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3.1.1 Precipitation

U.S. Department of the Interior; U.S. Geological Survey

U.S. Department of the Interior. "California Precipitation." The National Atlas of the United States of America, 2005.


As a class, locate Riverside on this map and determine which color band (amount of precipitation) it falls in. Next, identify where your school is on this map. Ask students if they notice oranges growing nearby. Given what you see on this map, where else in the state do you think orange trees would do well? Note: Orange trees can withstand a wide temperature range — from 35 degrees in the winter to 100 degrees in the summer. Freezing temperatures damage the fruit. The strong heat helps create more sweetness in the fruit. Oranges need a fair amount of water (they do best in areas that receive 40 – 45 inches of rain per year), but in areas with less rain (like Southern California), irrigation is critical for tree growth. Orange trees can handle drought well. Given these geographic needs, Riverside’s rainy, cool/cold winters and dry, hot summers make it an ideal place for growing citrus.
Where We Are


PRECIPITATION Precipitation varies widely across the United States, from a low of 2.3 inches per year in California's Death Valley to a high of 460 inches on Hawaii's Mount Waialeale. Nevada ranks as the driest state, with an average annual precipitation of 9.5 inches, and Hawaii is the wettest, at 70.3 inches. The average annual precipitation for California is 21.44 inches. Average Annual Precipitation (in inches)