September weather forecastClyde Hill, WA
September
Weather in September
The first month of the autumn, September, is still a pleasant month in Clyde Hill, Washington, with an average temperature ranging between max 70°F (21.1°C) and min 50°F (10°C).Temperature
The onset of September is marked by a minor decrease in temperature, transitioning from a warm 76.6°F (24.8°C) in August to a pleasant 70°F (21.1°C). Throughout September, the temperature falls to an average low of 50°F (10°C).Humidity
In September, the average relative humidity in Clyde Hill is 74%.Rainfall
In Clyde Hill, during September, the rain falls for 7.5 days and regularly aggregates up to 0.63" (16mm) of precipitation. Throughout the year, there are 119.1 rainfall days, and 11.97" (304mm) of precipitation is accumulated.Snowfall
April through October are months without snowfall.Daylight
In Clyde Hill, Washington, the average length of the day in September is 12h and 33min.On the first day of the month, sunrise is at 6:28 am and sunset at 7:48 pm. On the last day of September, in Clyde Hill, sunrise is at 7:07 am and sunset at 6:49 pm PDT.
Sunshine
The average sunshine in September is 9.3h.UV index
In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for the average person.Note: The daily high UV index of 4 during September translates into the following recommendations:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. Experience reduced UV exposure by about half when donning a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Clyde Hill, WA
- Average high temperature in September: 70°F
The warmest month (with the highest average high temperature) is August (76.6°F).
The month with the lowest average high temperature is December (42.8°F).
- Average low temperature in September: 50°F
The month with the highest average low temperature is August (53.4°F).
The coldest month (with the lowest average low temperature) is February (34.5°F).
Average pressure in September
Clyde Hill, WA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).
Average wind speed in September
Clyde Hill, WA
- Average wind speed in September: 3.7mph
The windiest month (with the highest average wind speed) is March (5.1mph).
The calmest month (with the lowest average wind speed) is August (3.4mph).
Average humidity in September
Clyde Hill, WA
- Average humidity in September: 74%
The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is July (69%).
Average rainfall in September
Clyde Hill, WA
- Average rainfall in September: 0.63"
The wettest month (with the highest rainfall) is December (2.01").
The driest month (with the least rainfall) is July (0.24").
Average rainfall days in September
Clyde Hill, WA
- Average rainfall days in September: 7.5 days
The month with the highest number of rainy days is March (13.7 days).
The month with the least rainy days is August (4.1 days).
Average snowfall in September
Clyde Hill, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.77").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Clyde Hill, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (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
Clyde Hill, 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 18min
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 12min).
Average sunshine days in September
Clyde Hill, WA
- Average sunshine days in September: 20.5 days
The month with the most sunshine days is August (24.9 days).
The month with the least sunshine days is February (13.8 days).
Average UV index in September
Clyde Hill, 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
Clyde Hill, WA
- Average cloud cover in September: 34
The month with the most cloud cover is December (Cloud cover 56).
The month with the least cloud cover is August (Cloud cover 25).
Average visibility in September
Clyde Hill, 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).
