San Francisco Climate

A San Francisco Climate is a Warm-Summer Mediterranean Climate that ...

• AKA: Climate.
• See: Köppen Climate Classification, La Niña, National Weather Service, Hardiness Zone, Warm-Summer Mediterranean Climate, California Current, San Francisco Bay, North Pacific High, Golden Gate, San Francisco Fog, San Francisco International Airport, El Niño.

---

---

References

2022

• (Wikipedia, 2022) ⇒ https://en.wikipedia.org/wiki/San_Francisco#Climate Retrieved:2022-9-28.
  • San Francisco has a warm-summer Mediterranean climate (Köppen Csb) characteristic of California's coast, with moist, cool winters and dry summers. San Francisco's weather is strongly influenced by the cool currents of the Pacific Ocean on the west side of the city, and the water of San Francisco Bay to the north and east. This moderates temperature swings and produces a remarkably mild year-round climate with little seasonal temperature variation. Among major U.S. cities, San Francisco has the coolest daily mean, maximum, and minimum temperatures for June, July, and August. During the summer, rising hot air in California's interior valleys creates a low-pressure area that draws winds from the North Pacific High through the Golden Gate, which creates the city's characteristic cool winds and fog. The fog is less pronounced in eastern neighborhoods and during the late summer and early fall. As a result, the year's warmest month, on average, is September, and on average, October is warmer than July, especially in daytime. Temperatures reach or exceed on an average of only 21 and 23 days a year at downtown and San Francisco International Airport (SFO), respectively. The dry period of May to October is mild to warm, with the normal monthly mean temperature peaking in September at . The rainy period of November to April is slightly cooler, with the normal monthly mean temperature reaching its lowest in January at . On average, there are 73 rainy days a year, and annual precipitation averages . Variation in precipitation from year to year is high. Above-average rain years are often associated with warm El Niño conditions in the Pacific while dry years often occur in cold water La Niña periods. In 2013 (a "La Niña" year), a record low of rainfall was recorded at downtown San Francisco, where records have been kept since 1849. Snowfall in the city is very rare, with only 10 measurable accumulations recorded since 1852, most recently in 1976 when up to fell on Twin Peaks. The highest recorded temperature at the official National Weather Service downtown observation stationwas on September 1, 2017. During that hot spell, the warmest ever night of was also recorded. The lowest recorded temperature was on December 11, 1932. The National Weather Service provides a helpful visual aid graphing the information in the table below to display visually by month the annual typical temperatures, the past year's temperatures, and record temperatures. During a normal year between 1991 and 2020 San Francisco would record a warmest night at and a coldest day at . The coldest daytime high since the station's opening in 1945 was recorded in December 1972 at . As a coastal city, San Francisco will be heavily affected by climate change. , sea levels are projected to rise by as much as , resulting in periodic flooding, rising groundwater levels, and lowland floods from more severe storms. San Francisco falls under the USDA 10b Plant hardiness zone.

---