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Bellingham, Washington climate
Csb Warm-summer Mediterranean
Bellingham has a mildly seasonal cool-temperate climate (Warm-summer Mediterranean, Köppen Csb). The hottest month is August with an average daily high near 22°C, while the coldest is December averaging around 2°C at night. Precipitation totals about 1140 mm a year and is strongly seasonal — January alone averages 168 mm while August barely receives 28 mm.
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 countsBellingham climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 8 | 9 | 11 | 14 | 17 | 20 | 22 | 22 | 19 | 15 | 10 | 7 |
| Avg temp (°C) | 5 | 6 | 8 | 10 | 13 | 16 | 18 | 18 | 15 | 11 | 7 | 5 |
| Avg low (°C) | 2 | 2 | 4 | 6 | 9 | 12 | 14 | 14 | 11 | 8 | 4 | 2 |
| Precipitation (mm) | 168 | 95 | 117 | 80 | 68 | 44 | 29 | 28 | 67 | 129 | 160 | 156 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | 8 | 9 | 11 | 14 | 17 | 20 |
| Avg temp (°C) | 5 | 6 | 8 | 10 | 13 | 16 |
| Avg low (°C) | 2 | 2 | 4 | 6 | 9 | 12 |
| Precipitation (mm) | 168 | 95 | 117 | 80 | 68 | 44 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 22 | 22 | 19 | 15 | 10 | 7 |
| Avg temp (°C) | 18 | 18 | 15 | 11 | 7 | 5 |
| Avg low (°C) | 14 | 14 | 11 | 8 | 4 | 2 |
| Precipitation (mm) | 29 | 28 | 67 | 129 | 160 | 156 |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 17 | 14 | 18 | 15 | 12 | 10 | 7 | 6 | 10 | 18 | 19 | 17 |
| Days with high ≥ 32°C (days) | — | — | — | — | — | 0.0 | 0.1 | 0.1 | — | — | — | — |
| Days with low ≤ 0°C (days) | 8 | 8 | 3 | 0.3 | — | — | — | — | — | 0.4 | 5 | 8 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 17 | 14 | 18 | 15 | 12 | 10 |
| Days with high ≥ 32°C (days) | — | — | — | — | — | 0.0 |
| Days with low ≤ 0°C (days) | 8 | 8 | 3 | 0.3 | — | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 7 | 6 | 10 | 18 | 19 | 17 |
| Days with high ≥ 32°C (days) | 0.1 | 0.1 | — | — | — | — |
| Days with low ≤ 0°C (days) | — | — | — | 0.4 | 5 | 8 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 77 | 73 | 77 | 75 | 70 | 70 | 52 | 51 | 55 | 71 | 77 | 77 |
| Clear days (≤ 30% cloud) | 3 | 4 | 3 | 2 | 4 | 4 | 11 | 11 | 9 | 5 | 3 | 3 |
| Partly cloudy days (30–70%) | 6 | 6 | 7 | 8 | 8 | 8 | 8 | 9 | 8 | 7 | 5 | 7 |
| Cloudy days (≥ 70%) | 22 | 18 | 22 | 20 | 19 | 18 | 12 | 11 | 13 | 19 | 22 | 22 |
| Relative humidity (%) | 91 | 87 | 85 | 81 | 78 | 79 | 77 | 77 | 79 | 84 | 90 | 91 |
| Wind speed (m/s) | 0.9 | 0.8 | 0.8 | 0.7 | 0.5 | 0.5 | 0.4 | 0.5 | 0.5 | 0.7 | 0.8 | 0.9 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 77 | 73 | 77 | 75 | 70 | 70 |
| Clear days (≤ 30% cloud) | 3 | 4 | 3 | 2 | 4 | 4 |
| Partly cloudy days (30–70%) | 6 | 6 | 7 | 8 | 8 | 8 |
| Cloudy days (≥ 70%) | 22 | 18 | 22 | 20 | 19 | 18 |
| Relative humidity (%) | 91 | 87 | 85 | 81 | 78 | 79 |
| Wind speed (m/s) | 0.9 | 0.8 | 0.8 | 0.7 | 0.5 | 0.5 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 52 | 51 | 55 | 71 | 77 | 77 |
| Clear days (≤ 30% cloud) | 11 | 11 | 9 | 5 | 3 | 3 |
| Partly cloudy days (30–70%) | 8 | 9 | 8 | 7 | 5 | 7 |
| Cloudy days (≥ 70%) | 12 | 11 | 13 | 19 | 22 | 22 |
| Relative humidity (%) | 77 | 77 | 79 | 84 | 90 | 91 |
| Wind speed (m/s) | 0.4 | 0.5 | 0.5 | 0.7 | 0.8 | 0.9 |
Methodology & sources
Temperature & precipitation — 1991–2020 normals computed from 27 years of daily observations at White Rock Campbell Scientific, a weather station, about 36 km from the city centre. The underlying daily records come from NOAA's global station network.
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.