September weather forecastSedro-Woolley, WA
September
Weather in September
The first month of the autumn, September, is still a refreshing month in Sedro-Woolley, Washington, with temperature in the range of an average low of 47.8°F (8.8°C) and an average high of 64.2°F (17.9°C).Temperature
September's onset introduces a mild reduction in the average high-temperature, from an agreeable 70.7°F (21.5°C) in August to a comfortable 64.2°F (17.9°C). During September, the temperature tends to dip to an average of 47.8°F (8.8°C) at night.Humidity
In Sedro-Woolley, Washington, the average relative humidity in September is 79%.Rainfall
In September, the rain falls for 13.5 days. Throughout September, 2.76" (70mm) of precipitation is accumulated. In Sedro-Woolley, during the entire year, the rain falls for 203.2 days and collects up to 49.72" (1263mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
In Sedro-Woolley, the average length of the day in September is 12h and 34min.On the first day of September, sunrise is at 6:27 am and sunset at 7:49 pm. On the last day of the month, sunrise is at 7:08 am and sunset at 6:49 pm PDT.
Sunshine
The average sunshine in September is 8.8h.UV index
In September, the average daily maximum UV index is 3. A UV Index reading of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for the ordinary person.Note: A daily maximum UV index of 3 in September translates into the following instructions:
Undertake protective steps - Recommendations to avoid sunburn are issued. For skin protection, it's recommended to minimize Sun exposure during its peak hours around midday. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Sedro-Woolley, WA
- Average high temperature in September: 64.2°F
The warmest month (with the highest average high temperature) is July (70.9°F).
The month with the lowest average high temperature is December (40.5°F).
- Average low temperature in September: 47.8°F
The month with the highest average low temperature is August (50.5°F).
The coldest months (with the lowest average low temperature) are February and December (32.5°F).
Average pressure in September
Sedro-Woolley, WA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).
Average wind speed in September
Sedro-Woolley, WA
- Average wind speed in September: 3.8mph
The windiest month (with the highest average wind speed) is November (5.7mph).
The calmest month (with the lowest average wind speed) is August (3.3mph).
Average humidity in September
Sedro-Woolley, WA
- Average humidity in September: 79%
The months with the highest relative humidity are January, February and March (86%).
The month with the lowest relative humidity is July (75%).
Average rainfall in September
Sedro-Woolley, WA
- Average rainfall in September: 2.76"
The wettest month (with the highest rainfall) is November (7.09").
The driest month (with the least rainfall) is July (0.98").
Average rainfall days in September
Sedro-Woolley, WA
- Average rainfall days in September: 13.5 days
The month with the highest number of rainy days is March (22.1 days).
The month with the least rainy days is August (9.4 days).
Average snowfall in September
Sedro-Woolley, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (4.96").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Sedro-Woolley, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (4.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Sedro-Woolley, WA
- Average daylight in September: 12h and 36min
The month with the longest days is June (Average daylight: 16h and 6min).
The month with the shortest days is December (Average daylight: 8h and 24min).
- Average sunshine in September: 8h and 48min
The month with the most sunshine is August (Average sunshine: 10h and 18min).
The month with the least sunshine is December (Average sunshine: 3h and 30min).
Average sunshine days in September
Sedro-Woolley, WA
- Average sunshine days in September: 14.5 days
The month with the most sunshine days is August (19.2 days).
The month with the least sunshine days is March (7.3 days).
Average UV index in September
Sedro-Woolley, WA
- Average UV index in September: 3
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).
Average cloud cover in September
Sedro-Woolley, WA
- Average cloud cover in September: 37
The month with the most cloud cover is December (Cloud cover 62).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in September
Sedro-Woolley, WA
- Average visibility in September: 5mi
The months with the highest visibility are June, July and August (6mi).
The months with the lowest visibility are January, February, March, April, May, September, October, November and December (5mi).





