Friday Harbor, WA weather in September
In September, Friday Harbor sees highs around 68°F and lows around 48°F: mild, with frequent rain. There are about 12 days with rain. Great for outdoor plans.
- Normal high
- 68°F
- Normal low
- 48°F
- Wet days
- 12
- 1.0 in total
- Muggy days
- 0
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 72°F | 64°F |
| Normal low | 49°F | 46°F |
| Chance of a wet day | 34% | 44% |
| Sunrise / sunset | 6:29 am / 7:54 pm | 7:10 am / 6:53 pm |
| Daylight | 13.4 h | 11.7 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Pacific Time).
A typical September day
- 6 am52°Fdew point 49°F
- 9 am59°Fdew point 52°F
- Noon64°Fdew point 52°F
- 3 pm66°Fdew point 52°F
- 6 pm62°Fdew point 52°F
- 9 pm56°Fdew point 51°F
NOAA hourly normals (local standard time) from Bellingham Intl Airport (28 mi away); average wind 5 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F20 of 30
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph1 of 30
- Hot dayshigh 90°F or more0 of 30
- Muggy daysdaily mean dew point 65°F or more0 of 30
- Wet daysat least 0.01 in of rain or melted snow12 of 30
- Notable rainat least 0.10 in3 of 30
- Freezing nightslow 32°F or below0 of 30
- Snow on the groundsnow depth 1 in or more0 of 30
Average days per September, counted from daily records for each year 1991-2020.
Rain in September
Normal precipitation is 1.0 in; a dry September brings about 0.7 in and a wet one about 1.2 in (25th and 75th percentiles). Days with half an inch or more are rare.
How September varies from year to year
- Warmest September, 1991-20202011: average high 71°F
- Coolest September2007: average high 64°F
- Wettest September2010: 3.0 in
- Driest September2012: no measurable precipitation
- Highest reading89°F (September 3, 2017)
- Lowest reading36°F (September 23, 2000)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
September compared with August and October
| August | September | October | |
|---|---|---|---|
| Normal high | 73°F | 68°F | 59°F |
| Normal low | 50°F | 48°F | 44°F |
| Wet days | 7 | 12 | 15 |
| Comfortable days | 26 | 20 | 3 |
| Daylight | 14.3 h | 12.6 h | 10.8 h |
Highs change by -5°F from August and -9°F into October.
Nearby alternatives in September
- Warmer: Leavenworth, WA127 mi · high 78°F · 4 wet days
- Drier: Kent, WA88 mi · high 72°F · 8 wet days
How Friday Harbor ranks in September
- Normal high359th warmest of 378 cities; 8th of 9 in Washington
- Wet days343rd driest of 378
- Comfortable days17th most of 342
What to pack for Friday Harbor in September
- A rain jacket or umbrella – rain on about 12 days
Heating and cooling
September has 213 heating degree days and 3 cooling degree days (base 65°F), 4% of the year's total heating and cooling demand.
Questions
How cold is Friday Harbor in September?
The normal high is 68°F and the normal low is 48°F. From 1991 to 2020 the coldest September reading was 36°F (September 23, 2000).
Does it rain a lot in Friday Harbor in September?
About 12 days in September have at least 0.01 in of precipitation, and the normal total is 1.0 in. The wettest September in 1991-2020 was in 2010 (3.0 in); the driest was in 2012, with no measurable precipitation.
Is September a good time to visit Friday Harbor?
September ranks 4th of 12 months on our comfort score for Friday Harbor (78 out of 100). It has about 20 comfortable days. The best months are July and August.
Where the numbers come from
- Temperature, rain and frost dates: Friday Harbor Airport (USW00094276), 0.9 mi SSW of the city center, 109 ft (51 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Snowfall and snow depth: Olga 2 Se (USC00456096), 11 mi ENE of the city center, 80 ft . NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour: Bellingham Intl Airport (USW00024217), 28 mi NE of the city center, 149 ft (91 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Bellingham Intl Airport (727976-24217), 28 mi NE of the city center, 151 ft (93 ft higher than the city). Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).