September weather forecastTrentwood, WA
September
Weather in September
September, the first month of the autumn in Trentwood, is still a pleasant month, with an average temperature ranging between max 72.5°F (22.5°C) and min 48.2°F (9°C).Temperature
In September, the meteorological conditions alter, with the average high-temperature shifting from a warm 83.3°F (28.5°C) in August to an agreeable 72.5°F (22.5°C). During September, Trentwood detects a significant contrast from its daytime temperatures, with nights averaging at a chilly 48.2°F (9°C).Humidity
The average relative humidity in September is 52%.Rainfall
In Trentwood, in September, it is raining for 7.9 days, with typically 0.63" (16mm) of accumulated precipitation. Throughout the year, there are 125.4 rainfall days, and 17.28" (439mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.35" (9mm) of snow. In Trentwood, during the entire year, snow falls for 56.4 days and aggregates up to 37.4" (950mm) of snow.Daylight
In Trentwood, the average length of the day in September is 12h and 33min.On the first day of September, sunrise is at 6:08 am and sunset at 7:28 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:29 pm PDT.
Sunshine
The average sunshine in September is 10.1h.UV index
In Trentwood, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.Note: In September, a regular UV index of 4 translates into these guidelines:
Take necessary precautions - Protection from skin and eye injury is mandatory. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized. Alert! The snow's reflection can amplify the UV radiation of the Sun nearly twice.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Trentwood, WA
- Average high temperature in September: 72.5°F
The warmest month (with the highest average high temperature) is August (83.3°F).
The month with the lowest average high temperature is December (32°F).
- Average low temperature in September: 48.2°F
The month with the highest average low temperature is August (55.9°F).
The coldest month (with the lowest average low temperature) is December (21.9°F).
Average pressure in September
Trentwood, WA
- Average pressure in September: 29.96"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in September
Trentwood, WA
- Average wind speed in September: 4.9mph
The windiest month (with the highest average wind speed) is April (6.1mph).
The calmest month (with the lowest average wind speed) is December (4.7mph).
Average humidity in September
Trentwood, WA
- Average humidity in September: 52%
The month with the highest relative humidity is January (91%).
The month with the lowest relative humidity is August (43%).
Average rainfall in September
Trentwood, WA
- Average rainfall in September: 0.63"
The wettest month (with the highest rainfall) is January (2.28").
The driest months (with the least rainfall) are July and August (0.35").
Average rainfall days in September
Trentwood, WA
- Average rainfall days in September: 7.9 days
The month with the highest number of rainy days is March (16 days).
The month with the least rainy days is July (5.1 days).
Average snowfall in September
Trentwood, WA
- Average snowfall in September: 0.35"
The month with the highest snowfall is January (10.51").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Trentwood, WA
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is December (13.9 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Trentwood, 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: 10h and 6min
The month with the most sunshine is August (Average sunshine: 12h and 0min).
The months with the least sunshine are January and December (Average sunshine: 3h and 48min).
Average sunshine days in September
Trentwood, WA
- Average sunshine days in September: 20.8 days
The month with the most sunshine days is July (24.3 days).
The month with the least sunshine days is March (10.3 days).
Average UV index in September
Trentwood, WA
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Trentwood, WA
- Average cloud cover in September: 21
The month with the most cloud cover is January (Cloud cover 62).
The months with the least cloud cover are July and August (Cloud cover 13).
Average visibility in September
Trentwood, WA
- Average visibility in September: 6mi
The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February and December (4mi).
