on December 22, 1990, during an extended period of frigid Arctic air, and its overall record low temperature is , set on February 9, 1933 during a historic cold air surge from the north. During spring, temperatures warm steadily and rapidly. Wintry weather is usually last experienced in April. Summery weather first arrives in May; the earliest temperature on record was on May 2. Major cold fronts typically stop arriving in May or June. Summer temperatures are hot, although are moderated somewhat by the cool breezes from the Great Salt Lake and by the city's elevation. The lack of cold fronts in summer allows the temperatures to become consistently hot due to powerful, long-lasting high pressure . Occasional thunderstorms give almost the only relief in temperatures. In an average year, 5 days hotter than , 23 days greater than , and 56 days greater than can be expected. However, such days also have very low humidity. The low humidity and the altitude create ideal conditions for radiational cooling, and hence, large swings in temperature. Summer nights are rather cool; the record low even in July is . July is the warmest month, with an average temperature of . Salt Lake City's record high minimum temperature is , set on July 18, 2016, and its record high temperature is , first set on July 26, 1960 and again on July 13, 2002 (although the temperature in 2002 was slightly higher). The last summer-like weather is typically experienced in September; the latest temperature was recorded on September 30. Temperatures cool down rapidly in fall. The first major cold fronts typically arrive anytime from September to October. The first winter-like weather is usually experienced in November. Salt Lake City's average yearly temperature is , and the freeze-free period lasts an average of 167 days, from April 30 to October 15, although it has lasted anywhere from 124 to 236 days. Freezing temperatures have occurred as early as September 13 (in 1928), and as late as May 28 (in 1954). Precipitation Both precipitation and humidity are highest from March through May and lowest from June through mid-September. Major sources of precipitation are winter snow storms originating in the Gulf of Alaska, late winter and spring rains from the Pineapple Express created in Hawaiian waters, and summer monsoons from the Gulf of California. The airport averages of precipitation per year, with bench areas receiving up