Seattle/Boeing Fld weather by month
Averages and records for each calendar month at Seattle/Boeing Fld, United States, from 1948 to 2026. The warmest month is July, averaging 25.0°C; the coolest is January at 8.3°C.
| Month | Avg high | Avg low | Record high | Record low | Years |
|---|---|---|---|---|---|
| January | 8.3°C | 2.1°C | 18.3°C25 January 2015 | −16.1°C31 January 1950 | 46 / 46 |
| February | 9.7°C | 2.7°C | 22.2°C13 February 2015 | −15.6°C1 February 1950 | 46 / 46 |
| March | 11.8°C | 3.8°C | 26.1°C29 March 2004 | −8.9°C4 March 1955 | 46 / 46 |
| April | 15.1°C | 6.0°C | 31.7°C18 April 2016 | −1.1°C7 April 1952 | 46 / 46 |
| May | 18.8°C | 9.2°C | 33.9°C21 May 1963 | −1.1°C1 May 1954 | 46 / 46 |
| June | 21.8°C | 12.0°C | 40.0°C28 June 2021 | 5.0°C12 June 1952 | 46 / 46 |
| July | 25.0°C | 14.0°C | 40.6°C29 July 2009 | 7.2°C3 July 1949 | 46 / 46 |
| August | 24.6°C | 14.2°C | 37.8°C9 August 1960 | 7.8°C30 August 1950 | 45 / 46 |
| September | 21.5°C | 11.7°C | 33.3°C16 September 2025 | 2.2°C30 September 1950 | 44 / 46 |
| October | 16.0°C | 8.0°C | 28.3°C16 October 2022 | −2.7°C28 October 2023 | 44 / 45 |
| November | 11.2°C | 4.4°C | 21.7°C8 November 2016 | −13.3°C15 November 1955 | 44 / 44 |
| December | 8.5°C | 2.7°C | 20.6°C10 December 2014 | −11.7°C16 December 1964 | 45 / 45 |
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 44 to 46 years each.
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Climate at nearby stations
The closest stations with twelve months of archive of their own, nearest first.
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.