San Clemente climate by month
Averages and records for each calendar month at San Clemente, United States, from 1945 to 2025. The warmest month is September, averaging 21.8°C; the coolest is January at 16.6°C.
| Month | Avg high | Avg low | Record high | Record low | Years |
|---|---|---|---|---|---|
| January | 16.6°C | 9.9°C | 28.9°C13 January 1975 | 2.2°C1 January 1976 | 21 / 28 |
| February | 16.7°C | 10.4°C | 26.7°C12 February 1971 | 4.4°C2 February 1979 | 25 / 28 |
| March | 16.9°C | 10.7°C | 30.0°C25 March 1988 | 3.9°C9 March 1976 | 26 / 28 |
| April | 17.6°C | 11.1°C | 31.1°C21 April 1987 | 5.0°C9 April 1945 | 27 / 29 |
| May | 17.9°C | 12.3°C | 30.0°C17 May 1978 | 6.7°C10 May 1979 | 26 / 29 |
| June | 19.5°C | 13.9°C | 32.2°C24 June 1976 | 10.0°C2 June 1946 | 28 / 29 |
| July | 20.7°C | 15.4°C | 30.0°C27 July 1977 | 11.1°C6 July 1946 | 27 / 29 |
| August | 21.7°C | 16.4°C | 29.4°C8 August 1971 | 12.2°C25 August 1946 | 27 / 29 |
| September | 21.8°C | 16.1°C | 35.6°C24 September 1978 | 11.1°C20 September 1946 | 27 / 29 |
| October | 21.0°C | 14.7°C | 34.4°C22 October 1965 | 6.7°C30 October 1971 | 25 / 27 |
| November | 18.7°C | 12.3°C | 32.2°C1 November 1966 | 5.0°C16 November 1964 | 24 / 28 |
| December | 16.9°C | 10.4°C | 26.1°C6 December 1979 | 3.3°C26 December 1982 | 19 / 27 |
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 19 to 28 years each.
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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.