September weather forecastSultan, WA
September
Weather in September
The first month of the autumn, September, is still a refreshing month in Sultan, Washington, with an average temperature fluctuating between 45°F (7.2°C) and 66.4°F (19.1°C).Temperature
As August shifts into September, a minor alteration in temperatures is observed, with average highs reducing from a moderately hot 73.4°F (23°C) to a refreshing 66.4°F (19.1°C). During September, the average low-temperature is a chilly 45°F (7.2°C).Humidity
In Sultan, the average relative humidity in September is 77%.Rainfall
In September, the rain falls for 12.8 days. Throughout September, 2.24" (57mm) of precipitation is accumulated. In Sultan, Washington, during the entire year, the rain falls for 200.6 days and collects up to 51.65" (1312mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
In September, the average length of the day in Sultan is 12h and 33min.On the first day of September, sunrise is at 6:26 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 7:06 am and sunset at 6:47 pm PDT.
Sunshine
The average sunshine in September is 8.7h.UV index
The average daily maximum UV index in September is 3. A UV Index estimate of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for average individuals.Note: In September, the maximum UV index of 3 suggests these recommendations:
Take necessary precautions - Suggestions to elude sunburn are provided. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Sultan, WA
- Average high temperature in September: 66.4°F
The warmest month (with the highest average high temperature) is August (73.4°F).
The month with the lowest average high temperature is December (38.3°F).
- Average low temperature in September: 45°F
The month with the highest average low temperature is August (48°F).
The coldest month (with the lowest average low temperature) is December (28.6°F).
Average pressure in September
Sultan, WA
- Average pressure in September: 30"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is August (29.99"Hg).
Average wind speed in September
Sultan, WA
- Average wind speed in September: 3.3mph
The windiest month (with the highest average wind speed) is January (4.8mph).
The calmest month (with the lowest average wind speed) is August (3.2mph).
Average humidity in September
Sultan, WA
- Average humidity in September: 77%
The months with the highest relative humidity are January, February and March (88%).
The month with the lowest relative humidity is July (72%).
Average rainfall in September
Sultan, WA
- Average rainfall in September: 2.24"
The wettest month (with the highest rainfall) is January (7.8").
The driest month (with the least rainfall) is August (0.79").
Average rainfall days in September
Sultan, WA
- Average rainfall days in September: 12.8 days
The month with the highest number of rainy days is March (22.3 days).
The month with the least rainy days is August (7.9 days).
Average snowfall in September
Sultan, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (5.43").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Sultan, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (5.2 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
Sultan, WA
- Average daylight in September: 12h and 36min
The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in September: 8h and 42min
The month with the most sunshine is August (Average sunshine: 10h and 24min).
The months with the least sunshine are January and December (Average sunshine: 3h and 42min).
Average sunshine days in September
Sultan, WA
- Average sunshine days in September: 15 days
The month with the most sunshine days is August (19.9 days).
The month with the least sunshine days is March (7 days).
Average UV index in September
Sultan, 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, April, October, November and December (UV index 2).
Average cloud cover in September
Sultan, WA
- Average cloud cover in September: 41
The months with the most cloud cover are March and December (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in September
Sultan, WA
- Average visibility in September: 5mi
The months with the highest visibility are May, June, July, August, September and October (5mi).
The months with the lowest visibility are January, February, March, April, November and December (4mi).
