September weather forecastUnderwood Heights, WA
September
Weather in September
The first month of the autumn, September, is also an agreeable month in Underwood Heights, Washington, with temperature in the range of an average high of 68.9°F (20.5°C) and an average low of 47.1°F (8.4°C).Temperature
The transition into September involves a decrease in the average high-temperature, falling from a warm 78.4°F (25.8°C) in August to a pleasant 68.9°F (20.5°C). In Underwood Heights, the September nights descend to a significantly cooler average of 47.1°F (8.4°C) compared to daytime highs.Humidity
In September, the average relative humidity in Underwood Heights is 66%.Rainfall
In Underwood Heights, during September, the rain falls for 9.2 days and regularly aggregates up to 1.14" (29mm) of precipitation. In Underwood Heights, during the entire year, the rain falls for 159.7 days and collects up to 31.42" (798mm) of precipitation.Snowfall
April through October are months without snowfall in Underwood Heights.Daylight
In Underwood Heights, the average length of the day in September is 12h and 31min.On the first day of September, sunrise is at 6:28 am and sunset at 7:43 pm. On the last day of the month, sunrise is at 7:04 am and sunset at 6:47 pm PDT.
Sunshine
The average sunshine in September in Underwood Heights is 9.9h.UV index
In Underwood Heights, the average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV rays for the ordinary person.Note: A maximum high UV index of 3 in September translates into the following recommendations:
Heed the precautions - It is counselled to guard against solar damage. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities 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
Underwood Heights, WA
- Average high temperature in September: 68.9°F
The warmest month (with the highest average high temperature) is August (78.4°F).
The month with the lowest average high temperature is December (36°F).
- Average low temperature in September: 47.1°F
The month with the highest average low temperature is August (51.4°F).
The coldest month (with the lowest average low temperature) is December (27°F).
Average pressure in September
Underwood Heights, WA
- Average pressure in September: 29.99"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is August (29.97"Hg).
Average wind speed in September
Underwood Heights, WA
- Average wind speed in September: 5mph
The windiest month (with the highest average wind speed) is June (6.1mph).
The calmest month (with the lowest average wind speed) is October (4.8mph).
Average humidity in September
Underwood Heights, WA
- Average humidity in September: 66%
The months with the highest relative humidity are February and December (88%).
The month with the lowest relative humidity is July (59%).
Average rainfall in September
Underwood Heights, WA
- Average rainfall in September: 1.14"
The wettest month (with the highest rainfall) is January (5.67").
The driest month (with the least rainfall) is July (0.28").
Average rainfall days in September
Underwood Heights, WA
- Average rainfall days in September: 9.2 days
The month with the highest number of rainy days is March (20 days).
The month with the least rainy days is August (4.2 days).
Average snowfall in September
Underwood Heights, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (4.76").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Underwood Heights, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (4.1 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
Underwood Heights, WA
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 42min).
The month with the shortest days is December (Average daylight: 8h and 42min).
- Average sunshine in September: 9h and 54min
The month with the most sunshine is July (Average sunshine: 11h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Underwood Heights, WA
- Average sunshine days in September: 18.7 days
The month with the most sunshine days is July (25.4 days).
The month with the least sunshine days is March (8.4 days).
Average UV index in September
Underwood Heights, WA
- Average UV index in September: 3
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February and November (UV index 1).
Average cloud cover in September
Underwood Heights, WA
- Average cloud cover in September: 29
The months with the most cloud cover are January and February (Cloud cover 64).
The months with the least cloud cover are July and August (Cloud cover 17).
Average visibility in September
Underwood Heights, 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 and December (4mi).
