September weather forecastSteilacoom, WA
September
Weather in September
September, the first month of the autumn in Steilacoom, is still a pleasant month, with temperature in the range of an average low of 49.5°F (9.7°C) and an average high of 70.9°F (21.6°C).Temperature
As August makes way for September, Steilacoom's average high-temperature eases from a moderately hot 78.1°F (25.6°C) to an agreeable 70.9°F (21.6°C). The average temperature in Steilacoom during September nights dips to a frosty 49.5°F (9.7°C).Humidity
The average relative humidity in September is 75%.Rainfall
In Steilacoom, during September, the rain falls for 11.9 days and regularly aggregates up to 1.54" (39mm) of precipitation. In Steilacoom, Washington, during the entire year, the rain falls for 172.9 days and collects up to 30.08" (764mm) of precipitation.Snowfall
April through October are months without snowfall.Daylight
In September, the average length of the day is 12h and 32min.On the first day of the month, sunrise is at 6:30 am and sunset at 7:49 pm. On the last day of September, in Steilacoom, sunrise is at 7:09 am and sunset at 6:51 pm PDT.
Sunshine
In Steilacoom, the average sunshine in September is 9h.UV index
In Steilacoom, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for ordinary individuals.Note: In September, a daily UV index of 4 turns into the following recommendations:
Undertake precautions - Obligation exists to protect against skin and eye damage. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Steilacoom, WA
- Average high temperature in September: 70.9°F
The warmest month (with the highest average high temperature) is August (78.1°F).
The month with the lowest average high temperature is December (43.7°F).
- Average low temperature in September: 49.5°F
The month with the highest average low temperature is August (52.7°F).
The coldest months (with the lowest average low temperature) are February and December (34.3°F).
Average pressure in September
Steilacoom, WA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.01"Hg).
Average wind speed in September
Steilacoom, WA
- Average wind speed in September: 4mph
The windiest month (with the highest average wind speed) is March (5.2mph).
The calmest month (with the lowest average wind speed) is August (3.7mph).
Average humidity in September
Steilacoom, WA
- Average humidity in September: 75%
The months with the highest relative humidity are January and December (87%).
The month with the lowest relative humidity is July (68%).
Average rainfall in September
Steilacoom, WA
- Average rainfall in September: 1.54"
The wettest month (with the highest rainfall) is December (4.69").
The driest month (with the least rainfall) is July (0.39").
Average rainfall days in September
Steilacoom, WA
- Average rainfall days in September: 11.9 days
The month with the highest number of rainy days is March (20.1 days).
The month with the least rainy days is August (5 days).
Average snowfall in September
Steilacoom, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.28").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Steilacoom, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (3.2 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
Steilacoom, 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 36min).
- Average sunshine in September: 9h and 0min
The month with the most sunshine is August (Average sunshine: 10h and 36min).
The month with the least sunshine is December (Average sunshine: 4h and 0min).
Average sunshine days in September
Steilacoom, WA
- Average sunshine days in September: 16.5 days
The month with the most sunshine days is August (23.4 days).
The month with the least sunshine days is February (9 days).
Average UV index in September
Steilacoom, WA
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Steilacoom, WA
- Average cloud cover in September: 36
The month with the most cloud cover is December (Cloud cover 59).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in September
Steilacoom, 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).
