Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
September's arrival comes with a decrease in the average high-temperature, moving from a moderately hot 78.4°F (25.8°C) in August to a pleasant 68.9°F (20.5°C). September presents a pronounced difference from daytime highs, with a consistent average low-temperature of 47.1°F (8.4°C).Humidity
The average relative humidity in September is 66%.Rainfall
In Underwood, Washington, in September, it is raining for 9.2 days, with typically 1.14" (29mm) of accumulated precipitation. Throughout the year, there are 159.7 rainfall days, and 31.42" (798mm) of precipitation is accumulated.Snowfall
In Underwood, snow does not fall in April through October.Daylight
In September, the average length of the day in Underwood, Washington, is 12h and 31min.On the first day of the month, sunrise is at 6:28 am and sunset at 7:43 pm. On the last day of September, sunrise is at 7:04 am and sunset at 6:47 pm PDT.
Sunshine
The average sunshine in September is 9.9h.UV index
In September, the average daily maximum UV index is 3. A UV Index estimate of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.Note: The UV index of 3 during September translates into the following guidance:
Make use of precautions - It is urged to ward off sun damage. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Underwood have in September?
What is the UV index intensity in September?
Average temperature in September
Underwood, 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, 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, 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, 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, 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, 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, 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, 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, WA
- Average daylight in September: 12h and 3min
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 5min
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, 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, 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, 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, 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).
Underwood, Washington, USA
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