Portland Intl climate by month
Averages and records for each calendar month at Portland Intl, United States, from 1938 to 2026. The warmest month is July, averaging 27.0°C; the coolest is January at 7.6°C.
| Month | Avg high | Avg low | Record high | Record low | Years |
|---|---|---|---|---|---|
| January | 7.6°C | 1.4°C | 18.9°C18 January 2005 | −18.9°C31 January 1950 | 88 / 88 |
| February | 10.3°C | 2.3°C | 21.7°C28 February 1988 | −19.4°C2 February 1950 | 88 / 88 |
| March | 13.2°C | 3.8°C | 27.8°C26 March 2025 | −7.2°C5 March 1955 | 88 / 88 |
| April | 16.3°C | 5.8°C | 32.2°C30 April 1998 | −1.7°C21 April 1951 | 89 / 89 |
| May | 20.1°C | 9.0°C | 37.8°C28 May 1983 | −1.7°C1 May 1954 | 89 / 89 |
| June | 23.1°C | 11.8°C | 46.7°C28 June 2021 | 3.9°C1 June 1966 | 89 / 89 |
| July | 27.0°C | 14.0°C | 41.7°C30 July 1965 | 6.1°C2 July 1955 | 89 / 89 |
| August | 26.9°C | 14.2°C | 42.2°C14 August 2023 | 6.7°C29 August 1951 | 89 / 89 |
| September | 24.0°C | 11.5°C | 40.6°C2 September 1988 | 1.1°C22 September 1961 | 88 / 89 |
| October | 17.7°C | 7.7°C | 33.3°C1 October 1987 | −3.3°C28 October 1946 | 88 / 88 |
| November | 11.5°C | 4.4°C | 22.8°C3 November 1975 | −10.6°C15 November 1955 | 88 / 88 |
| December | 8.0°C | 2.1°C | 19.4°C4 December 2023 | −14.4°C16 December 1964 | 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.
See what Portland Intl is doing right now
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.