San Francisco Intl climate by month
Averages and records for each calendar month at San Francisco Intl, United States, from 1945 to 2026. The warmest month is September, averaging 23.1°C; the coolest is January at 13.6°C.
| Month | Avg high | Avg low | Record high | Record low | Years |
|---|---|---|---|---|---|
| January | 13.6°C | 6.2°C | 23.3°C31 January 2015 | −3.3°C5 January 1949 | 81 / 81 |
| February | 15.3°C | 7.3°C | 25.6°C10 February 2022 | −1.1°C14 February 1949 | 80 / 81 |
| March | 16.4°C | 8.1°C | 31.7°C20 March 2026 | −0.6°C3 March 1966 | 81 / 81 |
| April | 17.9°C | 9.0°C | 33.3°C29 April 1981 | 2.2°C27 April 1955 | 81 / 81 |
| May | 19.4°C | 10.4°C | 36.1°C27 May 1984 | 3.9°C3 May 1950 | 81 / 81 |
| June | 21.2°C | 11.7°C | 40.6°C14 June 2000 | 6.1°C1 June 1954 | 80 / 81 |
| July | 21.9°C | 12.5°C | 37.2°C1 July 1985 | 6.7°C29 July 1951 | 81 / 82 |
| August | 22.3°C | 13.0°C | 37.2°C24 August 2010 | 7.2°C30 August 1952 | 81 / 82 |
| September | 23.1°C | 12.9°C | 40.0°C1 September 2017 | 5.0°C30 September 1950 | 81 / 82 |
| October | 21.5°C | 11.4°C | 37.2°C5 October 1987 | 2.8°C20 October 1949 | 81 / 81 |
| November | 17.3°C | 8.8°C | 29.4°C1 November 1967 | −0.6°C30 November 1954 | 81 / 81 |
| December | 13.7°C | 6.5°C | 23.9°C2 December 1958 | −4.4°C9 December 1972 | 81 / 81 |
Years shows the number behind the average high, then the number holding a record for that month. They differ because a year contributes an average only when the month has at least 25 days of readings, while a single reading is enough to set a record. The average low is withheld on the same 25-day rule and is counted separately again; it is shown as a dash where the archive cannot support it. Across the twelve months here the averages rest on 80 to 81 years each.
See what San Francisco Intl is doing right now
Every figure on this page is computed from NOAA GHCN-Daily observations stored per station, per year, per month. Nothing is modelled, interpolated or estimated, and a month the archive never covered is left out rather than filled in. A station appears here only once all twelve months carry an average from at least 10 years. See how this is built.