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 is characterized by a slight reduction in average high-temperature, easing from a moderately hot 75.7°F (24.3°C) in August to an agreeable 68.9°F (20.5°C). In the month of September, Sumner records a consistent average low-temperature of 47.7°F (8.7°C).Humidity
In September, the average relative humidity is 75%.Rainfall
In Sumner, in September, during 12.2 rainfall days, 1.61" (41mm) of precipitation is typically accumulated. Throughout the year, there are 185 rainfall days, and 35.71" (907mm) of precipitation is accumulated.Snowfall
May through October are months without snowfall in Sumner.Daylight
In Sumner, the average length of the day in September is 12h and 32min.On the first day of the month, sunrise is at 6:29 am and sunset at 7:48 pm. On the last day of September, in Sumner, Washington, sunrise is at 7:07 am and sunset at 6:49 pm PDT.
Sunshine
In Sumner, the average sunshine in September is 9.3h.UV index
The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for the average person.Note: In September, an average UV index of 4 transforms into the following instructions:
Be vigilant - A duty to shield skin and eyes from injury exists. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.
Frequently asked questions
What is the usual temperature for Sumner in September?
What is the average humidity in September in Sumner?
How much does it rain in Sumner in September?
When it does not snow in Sumner?
How many hours of daylight does Sumner have in September?
When is the sunrise / sunset in September in Sumner?
How many hours of sunshine does Sumner have in September?
How high is the UV index in September in Sumner?
Average temperature in September
Sumner, WA
- Average high temperature in September: 68.9°F
The warmest month (with the highest average high temperature) is August (75.7°F).
The month with the lowest average high temperature is December (41.4°F).
- Average low temperature in September: 47.7°F
The month with the highest average low temperature is August (50.9°F).
The coldest month (with the lowest average low temperature) is December (32°F).
Average pressure in September
Sumner, 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
Sumner, WA
- Average wind speed in September: 3.7mph
The windiest month (with the highest average wind speed) is January (4.9mph).
The calmest month (with the lowest average wind speed) is August (3.5mph).
Average humidity in September
Sumner, WA
- Average humidity in September: 75%
The month with the highest relative humidity is January (87%).
The months with the lowest relative humidity are July and August (70%).
Average rainfall in September
Sumner, WA
- Average rainfall in September: 1.61"
The wettest month (with the highest rainfall) is December (5.35").
The driest month (with the least rainfall) is July (0.51").
Average rainfall days in September
Sumner, WA
- Average rainfall days in September: 12.2 days
The month with the highest number of rainy days is March (20.7 days).
The month with the least rainy days is August (6.8 days).
Average snowfall in September
Sumner, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (3.31").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Sumner, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (5.3 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
Sumner, WA
- Average daylight in September: 12h and 3min
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 36min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is August (Average sunshine: 10h and 54min).
The month with the least sunshine is December (Average sunshine: 4h and 12min).
Average sunshine days in September
Sumner, WA
- Average sunshine days in September: 16.9 days
The month with the most sunshine days is August (22 days).
The month with the least sunshine days is February (8.2 days).
Average UV index in September
Sumner, WA
- Average UV index in September: 4
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in September
Sumner, WA
- Average cloud cover in September: 35
The months with the most cloud cover are January and December (Cloud cover 56).
The month with the least cloud cover is August (Cloud cover 25).
Average visibility in September
Sumner, WA
- Average visibility in September: 5mi
The months with the highest visibility are July and August (6mi).
The months with the lowest visibility are January, February and December (4mi).
Sumner, Washington, USA
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