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Forest Grove, Oregon climate
Csb Warm-summer Mediterranean
Forest Grove has a seasonal cool-temperate climate (Warm-summer Mediterranean, Köppen Csb). The hottest month is August with an average daily high near 28°C, while the coldest is December averaging around 0°C at night. Precipitation totals about 1187 mm a year and is strongly seasonal — December alone averages 221 mm while July barely receives 8 mm. Snow is occasional (7 cm of snow per year on average).
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresClear vs cloudy days
Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day countsForest Grove climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 7 | 10 | 13 | 16 | 20 | 23 | 27 | 28 | 25 | 17 | 11 | 7 |
| Avg temp (°C) | 4 | 5 | 7 | 10 | 14 | 16 | 20 | 20 | 17 | 11 | 6 | 4 |
| Avg low (°C) | 0 | 1 | 2 | 4 | 7 | 10 | 12 | 12 | 9 | 5 | 2 | 0 |
| Precipitation (mm) | 183 | 146 | 128 | 85 | 56 | 36 | 8 | 13 | 34 | 94 | 184 | 221 |
| Snowfall (cm) | 2 | 2 | — | — | — | — | — | — | — | 1 | — | 3 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | 7 | 10 | 13 | 16 | 20 | 23 |
| Avg temp (°C) | 4 | 5 | 7 | 10 | 14 | 16 |
| Avg low (°C) | 0 | 1 | 2 | 4 | 7 | 10 |
| Precipitation (mm) | 183 | 146 | 128 | 85 | 56 | 36 |
| Snowfall (cm) | 2 | 2 | — | — | — | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 27 | 28 | 25 | 17 | 11 | 7 |
| Avg temp (°C) | 20 | 20 | 17 | 11 | 6 | 4 |
| Avg low (°C) | 12 | 12 | 9 | 5 | 2 | 0 |
| Precipitation (mm) | 8 | 13 | 34 | 94 | 184 | 221 |
| Snowfall (cm) | — | — | — | 1 | — | 3 |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 16 | 13 | 16 | 14 | 10 | 7 | 2 | 3 | 5 | 11 | 15 | 16 |
| Days with high ≥ 32°C (days) | — | — | — | — | 1 | 2 | 7 | 8 | 3 | 0.1 | — | — |
| Days with low ≤ 0°C (days) | 13 | 12 | 8 | 3 | 0.2 | 0.0 | — | 0.0 | — | 2 | 9 | 12 |
| Days with snowfall ≥ 2.5 cm (days) | 0.2 | 0.1 | — | — | — | — | — | — | — | 0.0 | — | 0.3 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 16 | 13 | 16 | 14 | 10 | 7 |
| Days with high ≥ 32°C (days) | — | — | — | — | 1 | 2 |
| Days with low ≤ 0°C (days) | 13 | 12 | 8 | 3 | 0.2 | 0.0 |
| Days with snowfall ≥ 2.5 cm (days) | 0.2 | 0.1 | — | — | — | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 2 | 3 | 5 | 11 | 15 | 16 |
| Days with high ≥ 32°C (days) | 7 | 8 | 3 | 0.1 | — | — |
| Days with low ≤ 0°C (days) | — | 0.0 | — | 2 | 9 | 12 |
| Days with snowfall ≥ 2.5 cm (days) | — | — | — | 0.0 | — | 0.3 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 76 | 74 | 76 | 75 | 70 | 64 | 43 | 43 | 49 | 63 | 75 | 78 |
| Clear days (≤ 30% cloud) | 3 | 4 | 3 | 3 | 5 | 6 | 13 | 13 | 12 | 7 | 3 | 2 |
| Partly cloudy days (30–70%) | 7 | 5 | 6 | 6 | 7 | 9 | 10 | 10 | 7 | 7 | 6 | 6 |
| Cloudy days (≥ 70%) | 21 | 19 | 22 | 21 | 19 | 15 | 8 | 8 | 11 | 17 | 21 | 22 |
| Relative humidity (%) | 94 | 91 | 89 | 86 | 84 | 82 | 77 | 74 | 76 | 84 | 92 | 94 |
| Wind speed (km/h) | 2.3 | 2.2 | 2.2 | 2.1 | 1.9 | 1.9 | 1.9 | 2.0 | 1.9 | 2.1 | 2.3 | 2.3 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 76 | 74 | 76 | 75 | 70 | 64 |
| Clear days (≤ 30% cloud) | 3 | 4 | 3 | 3 | 5 | 6 |
| Partly cloudy days (30–70%) | 7 | 5 | 6 | 6 | 7 | 9 |
| Cloudy days (≥ 70%) | 21 | 19 | 22 | 21 | 19 | 15 |
| Relative humidity (%) | 94 | 91 | 89 | 86 | 84 | 82 |
| Wind speed (km/h) | 2.3 | 2.2 | 2.2 | 2.1 | 1.9 | 1.9 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 43 | 43 | 49 | 63 | 75 | 78 |
| Clear days (≤ 30% cloud) | 13 | 13 | 12 | 7 | 3 | 2 |
| Partly cloudy days (30–70%) | 10 | 10 | 7 | 7 | 6 | 6 |
| Cloudy days (≥ 70%) | 8 | 8 | 11 | 17 | 21 | 22 |
| Relative humidity (%) | 77 | 74 | 76 | 84 | 92 | 94 |
| Wind speed (km/h) | 1.9 | 2.0 | 1.9 | 2.1 | 2.3 | 2.3 |
Methodology & sources
Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Forest Grove (NOAA GHCN station USC00352997), inside the city.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.