September weather forecastTukwila, WA
September
Weather in September
September, the first month of the autumn in Tukwila, is still a pleasant month, with temperature in the range of an average low of 50.4°F (10.2°C) and an average high of 70.3°F (21.3°C).Temperature
A subtle change in temperatures is noted as August gives way to September, with average highs reducing from a moderately hot 77.7°F (25.4°C) to a pleasant 70.3°F (21.3°C). An average nighttime temperature of 50.4°F (10.2°C) is witnessed in Tukwila, Washington throughout September.Humidity
In Tukwila, the average relative humidity in September is 74%.Rainfall
In Tukwila, Washington, in September, during 10.5 rainfall days, 0.91" (23mm) of precipitation is typically accumulated. In Tukwila, Washington, during the entire year, the rain falls for 138.2 days and collects up to 14.09" (358mm) of precipitation.Snowfall
In Tukwila, snow does not fall in April through October.Daylight
In Tukwila, the average length of the day in September is 12h and 32min.On the first day of the month, sunrise is at 6:29 am and sunset at 7:48 pm. On the last day of September, in Tukwila, sunrise is at 7:07 am and sunset at 6:49 pm PDT.
Sunshine
In Tukwila, the average sunshine in September is 9.2h.UV index
The average daily maximum UV index in September in Tukwila is 4. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for ordinary individuals.Note: The maximum daily UV index of 4 in September interprets into the following recommendations:
Prioritize safety - Recommendations to avert sunburn are shared. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Tukwila, WA
- Average high temperature in September: 70.3°F
The warmest month (with the highest average high temperature) is August (77.7°F).
The month with the lowest average high temperature is December (43.5°F).
- Average low temperature in September: 50.4°F
The month with the highest average low temperature is August (53.6°F).
The coldest month (with the lowest average low temperature) is December (34.3°F).
Average pressure in September
Tukwila, WA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.01"Hg).
Average wind speed in September
Tukwila, WA
- Average wind speed in September: 3.9mph
The windiest month (with the highest average wind speed) is March (5.3mph).
The calmest months (with the lowest average wind speed) are July and August (3.6mph).
Average humidity in September
Tukwila, WA
- Average humidity in September: 74%
The months with the highest relative humidity are January and December (85%).
The month with the lowest relative humidity is July (68%).
Average rainfall in September
Tukwila, WA
- Average rainfall in September: 0.91"
The wettest month (with the highest rainfall) is December (2.2").
The driest month (with the least rainfall) is July (0.31").
Average rainfall days in September
Tukwila, WA
- Average rainfall days in September: 10.5 days
The month with the highest number of rainy days is April (14.9 days).
The month with the least rainy days is August (5.7 days).
Average snowfall in September
Tukwila, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.52").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Tukwila, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (3.4 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
Tukwila, WA
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in September: 9h and 12min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 6min).
Average sunshine days in September
Tukwila, WA
- Average sunshine days in September: 17.4 days
The month with the most sunshine days is August (22.8 days).
The month with the least sunshine days is February (13 days).
Average UV index in September
Tukwila, WA
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Tukwila, WA
- Average cloud cover in September: 35
The month with the most cloud cover is December (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 26).
Average visibility in September
Tukwila, WA
- Average visibility in September: 6mi
The months with the highest visibility are May, June, July, August and September (6mi).
The months with the lowest visibility are January, February, March, April, October, November and December (5mi).
