Bellingham weather in September: Bellingham, Washington: normal highs, lows, rain and records for September
Bellingham in September has a normal high of 68°F and a normal low of 50°F, a daily mean of 59°F, falling from 71°F on the 1st to 64°F by the 30th. Measurable precipitation falls on 11 days in a normal September, 2.01 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 20°C and low of 10°C, 51 mm of precipitation in September.
- NOAA stationBellingham International Airport
- Station IDUSW00024217
- Location48.79°N 122.54°W
- Elevation149 ft (45 m)
- From the center4 miles
- Population95,860
- Jan 46° 34°
- Feb 49° 35°
- Mar 53° 38°
- Apr 58° 42°
- May 64° 47°
- Jun 68° 52°
- Jul 73° 55°
- Aug 73° 55°
- Sep 68° 50°
- Oct 59° 43°
- Nov 51° 38°
- Dec 46° 34°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Bellingham in September?
The normal high is 68°F and the normal low 50°F, for a daily mean of 58.9°F. September is 5.0°F cooler than August and 7.8°F warmer than October. September is the 4th warmest month of the year in Bellingham and the 9th wettest. Across the month the normal high falls 7°F, from 71°F on September 1 to 64°F on September 30. From one year to the next September's mean temperature typically moves about 1.7°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 57°F and 61°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 44%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 71°F | 53°F | 28% | 14% |
| September 8 | 70°F | 51°F | 32% | 16% |
| September 15 | 69°F | 50°F | 36% | 18% |
| September 22 | 67°F | 48°F | 40% | 19% |
| September 30 | 64°F | 47°F | 44% | 22% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 1, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 71°F | 53°F | 28% | 14% | 13 h 30 min |
| September 2 | 71°F | 52°F | 29% | 14% | 13 h 30 min |
| September 3 | 71°F | 52°F | 29% | 14% | 13 h 20 min |
| September 4 | 71°F | 52°F | 30% | 14% | 13 h 20 min |
| September 5 | 71°F | 52°F | 30% | 15% | 13 h 20 min |
| September 6 | 70°F | 52°F | 31% | 15% | 13 h 10 min |
| September 7 | 70°F | 51°F | 31% | 15% | 13 h 10 min |
| September 8 | 70°F | 51°F | 32% | 16% | 13 h 10 min |
| September 9 | 70°F | 51°F | 33% | 16% | 13 h |
| September 10 | 70°F | 51°F | 33% | 16% | 13 h |
| September 11 | 69°F | 51°F | 34% | 16% | 12 h 50 min |
| September 12 | 69°F | 50°F | 34% | 17% | 12 h 50 min |
| September 13 | 69°F | 50°F | 35% | 17% | 12 h 50 min |
| September 14 | 69°F | 50°F | 36% | 17% | 12 h 40 min |
| September 15 | 69°F | 50°F | 36% | 18% | 12 h 40 min |
| September 16 | 68°F | 50°F | 37% | 18% | 12 h 40 min |
| September 17 | 68°F | 49°F | 38% | 18% | 12 h 30 min |
| September 18 | 68°F | 49°F | 38% | 18% | 12 h 30 min |
| September 19 | 68°F | 49°F | 39% | 19% | 12 h 30 min |
| September 20 | 67°F | 49°F | 39% | 19% | 12 h 20 min |
| September 21 | 67°F | 49°F | 40% | 19% | 12 h 20 min |
| September 22 | 67°F | 48°F | 40% | 19% | 12 h 20 min |
| September 23 | 66°F | 48°F | 41% | 20% | 12 h 10 min |
| September 24 | 66°F | 48°F | 41% | 20% | 12 h 10 min |
| September 25 | 66°F | 48°F | 42% | 20% | 12 h 10 min |
| September 26 | 65°F | 47°F | 42% | 21% | 12 h |
| September 27 | 65°F | 47°F | 43% | 21% | 12 h |
| September 28 | 65°F | 47°F | 43% | 21% | 11 h 50 min |
| September 29 | 64°F | 47°F | 44% | 22% | 11 h 50 min |
| September 30 | 64°F | 47°F | 44% | 22% | 11 h 50 min |
- Normal high
- 68°FSeptember average
- Normal low
- 50°FSeptember average
- Precipitation
- 2.01 inmonth total
- Days with precipitation
- 110.01 inch or more
- Daylight
- 13 h 30 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 10
- Days at 80°F or more
- 1
- Sunshine
- 76%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024217; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Bellingham in September?
On a given September day the chance of 0.01 inch or more is 36% on average, highest around September 30 (44%). In all, 2.01 in falls on 11 days of a normal September.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00024217.
How humid and windy is Bellingham in September?
At 3 p.m. the normal temperature is 62°F with 63% relative humidity and a dew point of 50°F; at 6 a.m. it is 49°F with 89% humidity. The wind averages 5.3 mph, most often from the south-southwest in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 49°F | 46°F | 89% | 4.4 mph | – |
| 9 a.m. | 55°F | 49°F | 80% | 6.2 mph | – |
| noon | 61°F | 49°F | 66% | 7.8 mph | 52% |
| 3 p.m. | 62°F | 50°F | 63% | 7.7 mph | 60% |
| 6 p.m. | 57°F | 50°F | 78% | 4.2 mph | 61% |
| 9 p.m. | 53°F | 48°F | 85% | 3.8 mph | 64% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024217. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for September in Bellingham?
The warmest September temperature on this station's record (since 1949) is 89°F, on September 14, 1951; the coldest is 28°F, on September 27, 1972. The wettest September brought 4.73 in (2019).
The September mean against the 1991-2020 normal of 58.9°F: 2021 59.4°F (+0.5), 2022 61.3°F (+2.4), 2023 58.9°F (at normal), 2024 58.3°F (−0.6), 2025 61.1°F (+2.2), 2026 57.0°F (−1.9). 3 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 59.4°F | +0.5°F | 4.49 in |
| 2022 | 61.3°F | +2.4°F | 0.00 in |
| 2023 | 58.9°F | at normal | 1.15 in |
| 2024 | 58.3°F | −0.6°F | 2.00 in |
| 2025 | 61.1°F | +2.2°F | 1.35 in |
| 2026 | 57.0°F | −1.9°F | 4.02 in |
Source: records: ACIS, station USW00024217; recent months: ACIS, station USW00024217. Records and recent months use complete months only.
How does September in Bellingham compare across Washington?
Across the 96 places PlainClimate covers in Washington, September normal highs run from 66°F in Coupeville to 81°F in Pasco; Bellingham's is 68°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.
Other months and places
- Bellingham in August73°F by day, 55°F at night
- Bellingham in October59°F by day, 43°F at night
- Bellingham through the yearEvery month, frost dates, records and recent years
- Washington in SeptemberThe statewide normal and the warmest and coolest places
- Pasco: Washington's warmest Septembernormal high 81°F