Tri-Cities weather by month
Measured at Pasco/Tri Cities Arpt
Averages and records for each calendar month at Pasco/Tri Cities Arpt, United States, from 1945 to 2026. The warmest month is July, averaging 34.4°C; the coolest is December at 5.1°C.
| Month | Avg high | Avg low | Record high | Record low | Years |
|---|---|---|---|---|---|
| January | 5.6°C | −2.2°C | 19.4°C7 January 2002 | −28.3°C4 January 2004 | 29 / 29 |
| February | 9.3°C | −2.0°C | 20.6°C10 February 2022 | −18.8°C6 February 2019 | 30 / 30 |
| March | 15.1°C | 0.8°C | 26.7°C30 March 2003 | −18.2°C4 March 2019 | 30 / 30 |
| April | 19.6°C | 3.5°C | 34.4°C30 April 1998 | −6.0°C1 April 2008 | 31 / 31 |
| May | 24.9°C | 8.1°C | 38.3°C23 May 2001 | −2.2°C5 May 1999 | 31 / 31 |
| June | 29.0°C | 11.8°C | 46.1°C27 June 2021 | 2.8°C7 June 2002 | 30 / 30 |
| July | 34.4°C | 14.4°C | 44.4°C23 July 2006 | 5.6°C5 July 1999 | 30 / 30 |
| August | 33.1°C | 13.8°C | 43.9°C4 August 1998 | 4.4°C31 August 2008 | 30 / 30 |
| September | 27.3°C | 9.1°C | 38.9°C1 September 2022 | −3.3°C24 September 2000 | 29 / 30 |
| October | 19.1°C | 3.9°C | 32.2°C6 October 2020 | −12.8°C31 October 2002 | 29 / 29 |
| November | 10.4°C | 0.0°C | 25.0°C13 November 1999 | −21.6°C24 November 2010 | 28 / 29 |
| December | 5.1°C | −2.5°C | 21.7°C1 December 2021 | −22.7°C16 December 2016 | 29 / 29 |
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 28 to 31 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.