San Bernardino Intl climate by month
Averages and records for each calendar month at San Bernardino Intl, United States, from 1949 to 2026. The warmest month is July, averaging 34.9°C; the coolest is January at 17.3°C.
| Month | Avg high | Avg low | Record high | Record low | Years |
|---|---|---|---|---|---|
| January | 17.3°C | 3.6°C | 30.0°C7 January 1962 | −6.7°C12 January 1949 | 24 / 24 |
| February | 19.5°C | 5.2°C | 35.0°C9 February 2026 | −3.3°C12 February 1965 | 24 / 24 |
| March | 20.6°C | 6.2°C | 39.0°C19 March 2026 | −1.7°C4 March 1966 | 24 / 24 |
| April | 23.0°C | 8.4°C | 37.2°C29 April 1959 | 0.0°C9 April 1953 | 24 / 24 |
| May | 25.7°C | 10.9°C | 40.0°C21 May 1967 | 2.2°C1 May 1967 | 23 / 24 |
| June | 29.7°C | 13.2°C | 44.4°C15 June 1961 | 4.4°C2 June 1967 | 24 / 24 |
| July | 34.9°C | 16.3°C | 42.8°C10 July 1958 | 10.0°C5 July 1955 | 24 / 24 |
| August | 34.9°C | 16.8°C | 43.3°C28 August 1967 | 8.9°C6 August 1950 | 24 / 24 |
| September | 32.6°C | 14.5°C | 45.0°C6 September 1955 | 6.7°C29 September 1955 | 23 / 24 |
| October | 27.7°C | 10.6°C | 40.6°C12 October 1950 | 1.7°C21 October 1949 | 23 / 23 |
| November | 22.2°C | 6.9°C | 34.4°C10 November 1968 | −2.8°C17 November 1958 | 23 / 23 |
| December | 18.4°C | 4.0°C | 31.0°C10 December 2025 | −4.4°C21 December 1968 | 22 / 22 |
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 22 to 24 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.