Bellingham weather by month
Bellingham runs from about 4°C in January to 19°C in July, with January the wettest month at 234 mm.
warmest month
July
19°C
coolest month
January
4°C
wettest month
January
234 mm
worst air month
September
17 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 4°C | 234 mm | 85 h | 9 |
| February | 5°C | 134 mm | 135 h | 8 |
| March | 7°C | 94 mm | 234 h | 8 |
| April | 9°C | 123 mm | 266 h | 11 |
| May | 12°C | 100 mm | 307 h | 10 |
| June | 14°C | 88 mm | 334 h | 9 |
| July | 19°C | 25 mm | 425 h | 8 |
| August | 18°C | 74 mm | 339 h | 12 |
| September | 16°C | 61 mm | 267 h | 17 |
| October | 11°C | 215 mm | 192 h | 8 |
| November | 7°C | 221 mm | 104 h | 8 |
| December | 6°C | 226 mm | 96 h | 8 |
About 2,784 hours of sun a year. Roughly 159 rainy days a year.
These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.
where these numbers come from
- · Temperature, rainfall and sunshine: ECMWF ERA5 reanalysis climate normals via Open-Meteo (CC BY 4.0), fetched once and stored.
- · PM2.5: Copernicus CAMS reanalysis, monthly means. Modelled, not station readings; near coasts CAMS counts sea salt as PM2.5 and reads high.
Last reviewed 2026-05-27. Full method, licences and the list of sources we rejected are on the methodology page.