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 tropical 87.4°F (30.8°C) in August to a moderately hot 76.6°F (24.8°C). The low-temperature in Prosser averages to a refreshing 56.1°F (13.4°C) during the nights of September.Humidity
The average relative humidity in September in Prosser is 45%.Rainfall
In Prosser, during September, the rain falls for 4.7 days and regularly aggregates up to 0.35" (9mm) of precipitation. Throughout the year, in Prosser, there are 97.8 rainfall days, and 7.44" (189mm) of precipitation is accumulated.Snowfall
January through March, September, November and December are months with snowfall. September is the first month it typically snows in Prosser, Washington. Throughout September, in the average 0.1 snowfall days, it receives 0.16" (4mm) of snow. Throughout the year, in Prosser, Washington, there are 13.5 snowfall days, and 5.87" (149mm) of snow is accumulated.Daylight
In September, the average length of the day is 12h and 31min.On the first day of September in Prosser, sunrise is at 6:20 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:40 pm PDT.
Sunshine
The average sunshine in September is 10.8h.UV index
In September, the average daily maximum UV index in Prosser is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for average individuals.Note: An average maximum UV index of 4 in September leads to these recommendations:
Proceed with care. Light skin individuals may be exposed to burns in fewer than 30 minutes. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage. Consider this! The reflection from snow can almost double the intensity of the Sun's UV radiation.
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Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures in Prosser?
What is the average humidity in September in Prosser?
How many days does it rain in September in Prosser?
When does it start snowing in Prosser?
What is the average length of the day in September in Prosser?
When is the sunrise / sunset in September in Prosser?
How long on average sun shines in September in Prosser?
What is the UV index intensity in September in Prosser?
Average temperature in September
Prosser, WA
- Average high temperature in September: 76.6°F
The warmest month (with the highest average high temperature) is July (88.3°F).
The month with the lowest average high temperature is December (37.2°F).
- Average low temperature in September: 56.1°F
The month with the highest average low temperature is August (63.1°F).
The coldest month (with the lowest average low temperature) is December (27°F).
Average pressure in September
Prosser, WA
- Average pressure in September: 29.96"Hg
The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in September
Prosser, WA
- Average wind speed in September: 6.8mph
The windiest month (with the highest average wind speed) is April (8.6mph).
The calmest month (with the lowest average wind speed) is December (5.6mph).
Average humidity in September
Prosser, WA
- Average humidity in September: 45%
The month with the highest relative humidity is January (81%).
The months with the lowest relative humidity are July and August (37%).
Average rainfall in September
Prosser, WA
- Average rainfall in September: 0.35"
The wettest months (with the highest rainfall) are January and December (0.94").
The driest month (with the least rainfall) is July (0.2").
Average rainfall days in September
Prosser, WA
- Average rainfall days in September: 4.7 days
The month with the highest number of rainy days is March (11.8 days).
The month with the least rainy days is July (3.6 days).
Average snowfall in September
Prosser, WA
- Average snowfall in September: 0.16"
The month with the highest snowfall is February (2.01").
The months with the least snowfall are April, May, June, July, August and October (0").
Average snowfall days in September
Prosser, WA
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is December (4.6 days).
The months with the least snowfall days are April, May, June, July, August and October (0 days).
Average daylight in September /
Average sunshine in September
Prosser, 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: 10h and 5min
The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is January (Average sunshine: 5h and 12min).
Average sunshine days in September
Prosser, WA
- Average sunshine days in September: 23.5 days
The month with the most sunshine days is July (25.8 days).
The month with the least sunshine days is February (15.5 days).
Average UV index in September
Prosser, WA
- Average UV index in September: 4
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Prosser, WA
- Average cloud cover in September: 16
The month with the most cloud cover is January (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 9).
Average visibility in September
Prosser, WA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Prosser, Washington, USA
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