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 onset brings a reduction in the average high-temperature, from a warm 82.8°F (28.2°C) in August to a pleasant 71.6°F (22°C). A marked difference from the daytime temperatures, Keller's nighttime temperature falls to an average low of 44.8°F (7.1°C) in September.Humidity
In Keller, the average relative humidity in September is 56%.Rainfall
In Keller, in September, during 5 rainfall days, 0.51" (13mm) of precipitation is typically accumulated. Throughout the year, there are 86.6 rainfall days, and 6.38" (162mm) of precipitation is accumulated.Snowfall
January through April, September, November and December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.47" (12mm) of snow. In Keller, during the entire year, snow falls for 24.6 days and aggregates up to 6.34" (161mm) of snow.Daylight
In September, the average length of the day is 12h and 33min.On the first day of September, sunrise is at 6:13 am and sunset at 7:35 pm. On the last day of the month, sunrise is at 6:53 am and sunset at 6:35 pm PDT.
Sunshine
In September, the average sunshine is 10.3h.UV index
The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for the average person.Note: An average UV index of 4 in September transforms into this advice:
Be vigilant - A duty to shield skin and eyes from injury exists. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days. Take into account! The reflection from snow can nearly double the Sun's UV radiation intensity.
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 does it start snowing?
What is the average length of the day in September?
When are sunrise and sunset in September in Keller?
How long on average sun shines in September?
What is the UV index reading in September?
Average temperature in September
Keller, WA
- Average high temperature in September: 71.6°F
The warmest month (with the highest average high temperature) is August (82.8°F).
The month with the lowest average high temperature is December (29.7°F).
- Average low temperature in September: 44.8°F
The month with the highest average low temperature is August (52.3°F).
The coldest months (with the lowest average low temperature) are February and December (18.3°F).
Average pressure in September
Keller, WA
- Average pressure in September: 29.97"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The months with the lowest atmospheric pressure are June and August (29.91"Hg).
Average wind speed in September
Keller, WA
- Average wind speed in September: 3.9mph
The windiest month (with the highest average wind speed) is April (4.6mph).
The calmest months (with the lowest average wind speed) are January and December (3.4mph).
Average humidity in September
Keller, WA
- Average humidity in September: 56%
The month with the highest relative humidity is January (94%).
The month with the lowest relative humidity is August (47%).
Average rainfall in September
Keller, WA
- Average rainfall in September: 0.51"
The wettest month (with the highest rainfall) is May (1.06").
The driest month (with the least rainfall) is August (0.31").
Average rainfall days in September
Keller, WA
- Average rainfall days in September: 5 days
The month with the highest number of rainy days is May (11.3 days).
The months with the least rainy days are February and September (5 days).
Average snowfall in September
Keller, WA
- Average snowfall in September: 0.47"
The month with the highest snowfall is January (1.42").
The months with the least snowfall are May, June, July, August and October (0").
Average snowfall days in September
Keller, WA
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is December (7.5 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Keller, WA
- Average daylight in September: 12h and 4min
The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 24min).
- Average sunshine in September: 10h and 2min
The month with the most sunshine is August (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Keller, WA
- Average sunshine days in September: 23.8 days
The month with the most sunshine days is September (23.8 days).
The month with the least sunshine days is June (17.3 days).
Average UV index in September
Keller, 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 1).
Average cloud cover in September
Keller, WA
- Average cloud cover in September: 20
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 13).
Average visibility in September
Keller, WA
- Average visibility in September: 6mi
The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The month with the lowest visibility is January (2mi).
Keller, Washington, USA
Weather forecast for your location
2. Allow the app to use your location