section_path: Geography/Climate
section_name: Climate
paragraph_text: Climate
  
  Los Angeles has a two-season semi-arid climate (Köppen: BSh) with dry summers and very mild winters, but it receives more annual precipitation than most semi-arid climates, narrowly missing the boundary of a Mediterranean climate (Köppen: Csb on the coast, Csa otherwise). Daytime temperatures are generally temperate all year round. In winter, they average around 68 °F (20 °C). Autumn months tend to be hot, with major heat waves a common occurrence in September and October, while the spring months tend to be cooler and experience more precipitation. Los Angeles has plenty of sunshine throughout the year, with an average of only 35 days with measurable precipitation annually.
  
  Temperatures in the coastal basin exceed 90 °F (32 °C) on a dozen or so days in the year, from one day a month in April, May, June and November to three days a month in July, August, October and to five days in September. Temperatures in the San Fernando and San Gabriel Valleys are considerably warmer. Temperatures are subject to substantial daily swings; in inland areas the difference between the average daily low and the average daily high is over 30 °F (17 °C). The average annual temperature of the sea is 63 °F (17 °C), from 58 °F (14 °C) in January to 68 °F (20 °C) in August. Hours of sunshine total more than 3,000 per year, from an average of 7 hours of sunshine per day in December to an average of 12 in July.
  
  Due to the mountainous terrain of the surrounding region, the Los Angeles area contains a large number of distinct microclimates, causing extreme variations in temperature in close physical proximity to each other. For example, the average July maximum temperature at the Santa Monica Pier is 70 °F (21 °C) whereas it is 95 °F (35 °C) in Canoga Park, 15 miles (24 km) away. The city, like much of the Southern Californian coast, is subject to a late spring/early summer weather phenomenon called " June Gloom ". This involves overcast or foggy skies in the morning that yield to sun by early afternoon.
  
  More recently, statewide droughts in California have further strained the city's water security. Downtown Los Angeles averages 14.67 in (373 mm) of precipitation annually, mainly occurring between November and March, generally in the form of moderate rain showers, but sometimes as heavy rainfall during winter storms. Rainfall is usually higher in the hills and coastal slopes of the mountains because of orographic uplift. Summer days are usually rainless. Rarely, an incursion of moist air from the south or east can bring brief thunderstorms in late summer, especially to the mountains. The coast gets slightly less rainfall, while the inland and mountain areas get considerably more. Years of average rainfall are rare. The usual pattern is a year-to-year variability, with a short string of dry years of 5–10 in (130–250 mm) rainfall, followed by one or two wet years with more than 20 in (510 mm). Wet years are usually associated with warm water El Niño conditions in the Pacific, dry years with cooler water La Niña episodes. A series of rainy days can bring floods to the lowlands and mudslides to the hills, especially after wildfires have denuded the slopes.
  
  Both freezing temperatures and snowfall are extremely rare in the city basin and along the coast, with the last occurrence of a 32 °F (0 °C) reading at the downtown station being January 29, 1979; freezing temperatures occur nearly every year in valley locations while the mountains within city limits typically receive snowfall every winter. The greatest snowfall recorded in downtown Los Angeles was 2.0 inches (5 cm) on January 15, 1932. While the most recent snowfall occurred in February 2019, the first snowfall since 1962, with snow falling in areas adjacent to Los Angeles as recently as January 2021. Brief, localized instances of hail can occur on rare occasions, but are more common than snowfall. At the official downtown station, the highest recorded temperature is 113 °F (45 °C) on September 27, 2010, while the lowest is 28 °F (−2 °C), on January 4, 1949. Within the City of Los Angeles, the highest temperature ever officially recorded is 121 °F (49 °C), on September 6, 2020, at the weather station at Pierce College in the San Fernando Valley neighborhood of Woodland Hills. During autumn and winter, Santa Ana winds sometimes bring much warmer and drier conditions to Los Angeles, and raise wildfire risk.