St Louis/Lambert Intl climate by month
Averages and records for each calendar month at St Louis/Lambert Intl, United States, from 1938 to 2026. The warmest month is July, averaging 31.9°C; the coolest is January at 4.1°C.
| Month | Avg high | Avg low | Record high | Record low | Years |
|---|---|---|---|---|---|
| January | 4.1°C | −5.3°C | 25.0°C24 January 1950 | −27.8°C20 January 1985 | 88 / 88 |
| February | 6.9°C | −3.2°C | 30.0°C27 February 2024 | −24.4°C3 February 1996 | 88 / 88 |
| March | 13.0°C | 1.9°C | 33.9°C26 March 2026 | −20.6°C5 March 1960 | 88 / 88 |
| April | 19.6°C | 8.0°C | 33.9°C26 April 1989 | −5.6°C8 April 1972 | 89 / 89 |
| May | 24.7°C | 13.6°C | 36.7°C26 May 1953 | −0.6°C10 May 1966 | 89 / 89 |
| June | 29.7°C | 18.9°C | 42.2°C28 June 2012 | 6.1°C3 June 1969 | 89 / 89 |
| July | 31.9°C | 21.2°C | 46.1°C14 July 1954 | 10.6°C27 July 1962 | 89 / 89 |
| August | 31.0°C | 20.2°C | 41.7°C29 August 1984 | 8.3°C29 August 1965 | 89 / 89 |
| September | 27.1°C | 15.6°C | 40.0°C4 September 1954 | 0.0°C28 September 1942 | 88 / 89 |
| October | 20.9°C | 9.2°C | 34.4°C2 October 1953 | −5.6°C26 October 1942 | 88 / 88 |
| November | 12.7°C | 2.6°C | 29.4°C1 November 1950 | −17.2°C30 November 1964 | 88 / 88 |
| December | 6.4°C | −2.6°C | 25.6°C28 December 2025 | −26.7°C22 December 1989 | 88 / 88 |
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 88 to 89 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.