September weather forecastBonneville, OR
September
Weather in September
The first month of the autumn, September, is also an enjoyable month in Bonneville, Oregon, with an average temperature varying between 45.7°F (7.6°C) and 67.5°F (19.7°C).Temperature
Welcoming September, Bonneville observes a shift in the average high-temperature, falling from August's moderately hot 76.5°F (24.7°C) to a refreshing 67.5°F (19.7°C). From the heights of the September heat, Bonneville records a mean nighttime low of 45.7°F (7.6°C).Humidity
In September, the average relative humidity is 72%.Rainfall
In Bonneville, in September, during 8.4 rainfall days, 1.1" (28mm) of precipitation is typically accumulated. Throughout the year, there are 158.4 rainfall days, and 30.31" (770mm) of precipitation is accumulated.Snowfall
April through October are months without snowfall.Daylight
In September, the average length of the day is 12h and 31min.On the first day of September, sunrise is at 6:30 am and sunset at 7:44 pm. On the last day of the month, sunrise is at 7:05 am and sunset at 6:49 pm PDT.
Sunshine
The average sunshine in September is 8.7h.UV index
The average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for the average person.Note: The maximum daily UV index of 3 in September converts into the following recommendations:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. Direct Sun exposure should be minimized especially during midday when radiation is most intense. Experience reduced UV exposure by about half when donning a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Bonneville, OR
- Average high temperature in September: 67.5°F
The warmest month (with the highest average high temperature) is August (76.5°F).
The month with the lowest average high temperature is December (37.9°F).
- Average low temperature in September: 45.7°F
The month with the highest average low temperature is August (48.7°F).
The coldest month (with the lowest average low temperature) is December (28.2°F).
Average pressure in September
Bonneville, OR
- Average pressure in September: 30"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is August (29.98"Hg).
Average wind speed in September
Bonneville, OR
- Average wind speed in September: 4.5mph
The windiest month (with the highest average wind speed) is January (6.8mph).
The calmest month (with the lowest average wind speed) is August (4.2mph).
Average humidity in September
Bonneville, OR
- Average humidity in September: 72%
The month with the highest relative humidity is February (89%).
The months with the lowest relative humidity are July and August (67%).
Average rainfall in September
Bonneville, OR
- Average rainfall in September: 1.1"
The wettest month (with the highest rainfall) is January (5.35").
The driest month (with the least rainfall) is July (0.28").
Average rainfall days in September
Bonneville, OR
- Average rainfall days in September: 8.4 days
The month with the highest number of rainy days is March (18.9 days).
The month with the least rainy days is July (4.4 days).
Average snowfall in September
Bonneville, OR
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.62").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Bonneville, OR
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (3.8 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
Bonneville, OR
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- Average sunshine in September: 8h and 42min
The months with the most sunshine are July and August (Average sunshine: 10h and 54min).
The month with the least sunshine is February (Average sunshine: 3h and 12min).
Average sunshine days in September
Bonneville, OR
- Average sunshine days in September: 20.1 days
The month with the most sunshine days is July (24.5 days).
The month with the least sunshine days is February (9.4 days).
Average UV index in September
Bonneville, OR
- Average UV index in September: 3
The months with the highest UV index are June and July (UV index 5).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
Bonneville, OR
- Average cloud cover in September: 39
The month with the most cloud cover is February (Cloud cover 68).
The months with the least cloud cover are July and August (Cloud cover 26).
Average visibility in September
Bonneville, OR
- Average visibility in September: 5mi
The months with the highest visibility are May, June, July, August, September and October (5mi).
The months with the lowest visibility are January, February, March, April, November and December (4mi).
