Climate averages 1991–2020
Bellingham weather
in September.
A mild, moderately wet month: the 3rd warmest and the 4th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Bellingham: daytime highs average 19.0°C and nights cool to about 11.8°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 81 mm of rain on roughly 9 days, which makes September a moderately wet month (the 4th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 39 min on an average September day.
The nearest other city in this atlas is Abbotsford (37 km away). In September its highs average 19.5°C, about as warm as Bellingham, with 102 mm of rain.
Among the 498 cities listed in the United States, Bellingham ranks 497th of 498 for the warmest September highs and joint 282nd of 498 for the driest September (rainfall, lowest first). The mean September high of those 498 cities is 26.9°C; Bellingham is 7.9°C cooler than that mean.
From September to October, average highs fall by 5.4°C to 13.6°C, and monthly rainfall rises from 81 mm to 162 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Bellingham climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 6.4°C1.2°C | 1.2°C | 213 | 18.6 | 8.89 h |
| February | 7.8°C1.2°C | 1.2°C | 139 | 15.5 | 10.110 h |
| March | 9.8°C2.6°C | 2.6°C | 171 | 18.9 | 11.912 h |
| April | 12.5°C4.7°C | 4.7°C | 122 | 15.2 | 13.714 h |
| May | 15.9°C8.1°C | 8.1°C | 86 | 11.3 | 15.215 h |
| June | 17.9°C11.1°C | 11.1°C | 64 | 9.4 | 16.116 h |
| July | 21.2°C13.8°C | 13.8°C | 32 | 5.1 | 15.716 h |
| August | 21.7°C14.2°C | 14.2°C | 46 | 5.3 | 14.414 h |
| September, selected | 19.0°C11.8°C | 11.8°C | 81 | 9.1 | 12.613 h |
| October | 13.6°C7.7°C | 7.7°C | 162 | 14.7 | 10.911 h |
| November | 8.7°C3.8°C | 3.8°C | 240 | 18.8 | 9.29 h |
| December | 5.8°C1.3°C | 1.3°C | 206 | 18.3 | 8.48 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Abbotsford in SeptemberCanada · 37 kmHigh 19.5°C · Low 9.8°C · 102 mm rain
- Langley in SeptemberCanada · 40 kmHigh 20.1°C · Low 10.9°C · 86 mm rain
- Surrey in SeptemberCanada · 46 kmHigh 19.6°C · Low 10.7°C · 86 mm rain
- Maple Ridge in SeptemberCanada · 52 kmHigh 20.0°C · Low 10.9°C · 173 mm rain
- Delta in SeptemberCanada · 55 kmHigh 19.6°C · Low 12.0°C · 72 mm rain
- New Westminster in SeptemberCanada · 59 kmHigh 19.3°C · Low 10.7°C · 125 mm rain
- Chilliwack in SeptemberCanada · 60 kmHigh 20.5°C · Low 11.4°C · 124 mm rain
- Coquitlam in SeptemberCanada · 62 kmHigh 20.0°C · Low 11.7°C · 142 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Bellingham) is explained once on the Bellingham year overview and on the Sources, method and limits page.