September weather forecastJefferson, OR
September
Weather in September
September, the first month of the autumn in Jefferson, is also a moderately hot month, with an average temperature varying between 50.2°F (10.1°C) and 73.8°F (23.2°C).Temperature
In September, the average high-temperature marginally drops from a warm 81.9°F (27.7°C) in August to a still moderately hot 73.8°F (23.2°C). Jefferson sees a large disparity in day to night temperatures in September, with the night temperature dropping to an average of 50.2°F (10.1°C).Humidity
The average relative humidity in September is 72%.Rainfall
In Jefferson, during September, the rain falls for 9.6 days and regularly aggregates up to 1.34" (34mm) of precipitation. Throughout the year, there are 164.2 rainfall days, and 26.97" (685mm) of precipitation is accumulated.Snowfall
April through October are months without snowfall in Jefferson.Daylight
In September, the average length of the day is 12h and 30min.On the first day of September, sunrise is at 6:35 am and sunset at 7:48 pm. On the last day of the month, sunrise is at 7:09 am and sunset at 6:53 pm PDT.
Sunshine
In September, the average sunshine is 9.4h.UV index
In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for the ordinary person.Note: The maximum daily UV index of 4 during September translates into the following directions:
Proceed with care. Light skin individuals may be exposed to burns in fewer than 30 minutes. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Jefferson, OR
- Average high temperature in September: 73.8°F
The warmest month (with the highest average high temperature) is August (81.9°F).
The month with the lowest average high temperature is December (45.5°F).
- Average low temperature in September: 50.2°F
The month with the highest average low temperature is August (52.9°F).
The coldest month (with the lowest average low temperature) is December (34.5°F).
Average pressure in September
Jefferson, OR
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).
Average wind speed in September
Jefferson, OR
- Average wind speed in September: 4.1mph
The windiest month (with the highest average wind speed) is March (5.1mph).
The calmest month (with the lowest average wind speed) is August (4mph).
Average humidity in September
Jefferson, OR
- Average humidity in September: 72%
The months with the highest relative humidity are February and December (87%).
The month with the lowest relative humidity is August (66%).
Average rainfall in September
Jefferson, OR
- Average rainfall in September: 1.34"
The wettest month (with the highest rainfall) is December (3.98").
The driest month (with the least rainfall) is July (0.24").
Average rainfall days in September
Jefferson, OR
- Average rainfall days in September: 9.6 days
The month with the highest number of rainy days is March (20 days).
The month with the least rainy days is August (3.9 days).
Average snowfall in September
Jefferson, OR
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.3").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Jefferson, OR
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (1.9 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Jefferson, OR
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in September: 9h and 24min
The month with the most sunshine is August (Average sunshine: 11h and 6min).
The month with the least sunshine is February (Average sunshine: 4h and 6min).
Average sunshine days in September
Jefferson, OR
- Average sunshine days in September: 19.1 days
The month with the most sunshine days is July (25.7 days).
The month with the least sunshine days is February (9 days).
Average UV index in September
Jefferson, OR
- 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 2).
Average cloud cover in September
Jefferson, OR
- Average cloud cover in September: 31
The month with the most cloud cover is February (Cloud cover 60).
The month with the least cloud cover is August (Cloud cover 21).
Average visibility in September
Jefferson, OR
- Average visibility in September: 6mi
The months with the highest visibility are July, August and September (6mi).
The month with the lowest visibility is February (4mi).
