September weather forecastThree Rivers, OR
September
Weather in September
The first month of the autumn, September, is still a pleasant month in Three Rivers, Oregon, with an average temperature fluctuating between 69.8°F (21°C) and 45.5°F (7.5°C).Temperature
September is marked by a subtle drop in average high-temperatures, transitioning from a warm 78.3°F (25.7°C) in August to an agreeable 69.8°F (21°C). Three Rivers experiences a consistent, yet significant, drop from daily highs to a low-temperature of 45.5°F (7.5°C) throughout September.Humidity
The average relative humidity in September is 54%.Rainfall
In September, the rain falls for 3.5 days. Throughout September, 0.24" (6mm) of precipitation is accumulated. In Three Rivers, during the entire year, the rain falls for 42.7 days and collects up to 4.8" (122mm) of precipitation.Snowfall
Months with snowfall are January through June, September through December. September is the first month it typically snows. Throughout September, in the average 0.6 snowfall days, it receives 0.43" (11mm) of snow. Throughout the year, there are 40.2 snowfall days, and 19.09" (485mm) of snow is accumulated.Daylight
In September, the average length of the day is 12h and 29min.On the first day of the month, sunrise is at 6:30 am and sunset at 7:40 pm. On the last day of September, sunrise is at 7:03 am and sunset at 6:47 pm PDT.
Sunshine
The average sunshine in September in Three Rivers is 11h.UV index
In Three Rivers, the average daily maximum UV index in September is 3. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for the ordinary person.Note: The UV index of 3 in September translates into these instructions:
Take measures. Individuals with light skin might experience burns in under 30 minutes. Around midday, solar radiation is most harmful; hence, exposure should be limited. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Watch out! The Sun's UV radiation can be nearly magnified twofold due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Three Rivers, OR
- Average high temperature in September: 69.8°F
The warmest month (with the highest average high temperature) is July (79.3°F).
The month with the lowest average high temperature is December (34.5°F).
- Average low temperature in September: 45.5°F
The month with the highest average low temperature is August (51.8°F).
The coldest month (with the lowest average low temperature) is December (23.7°F).
Average pressure in September
Three Rivers, OR
- Average pressure in September: 29.99"Hg
The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is August (29.97"Hg).
Average wind speed in September
Three Rivers, OR
- Average wind speed in September: 5.7mph
The windiest month (with the highest average wind speed) is March (7.6mph).
The calmest month (with the lowest average wind speed) is August (5.5mph).
Average humidity in September
Three Rivers, OR
- Average humidity in September: 54%
The month with the highest relative humidity is December (82%).
The month with the lowest relative humidity is July (46%).
Average rainfall in September
Three Rivers, OR
- Average rainfall in September: 0.24"
The wettest month (with the highest rainfall) is February (0.71").
The driest month (with the least rainfall) is July (0.08").
Average rainfall days in September
Three Rivers, OR
- Average rainfall days in September: 3.5 days
The month with the highest number of rainy days is May (5.5 days).
The month with the least rainy days is February (2.3 days).
Average snowfall in September
Three Rivers, OR
- Average snowfall in September: 0.43"
The month with the highest snowfall is February (4.61").
The months with the least snowfall are July and August (0").
Average snowfall days in September
Three Rivers, OR
- Average snowfall days in September: 0.6 days
The month with the highest number of snowfall days is December (7.4 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Three Rivers, OR
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in September: 11h and 0min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 30min).
Average sunshine days in September
Three Rivers, OR
- Average sunshine days in September: 24.4 days
The month with the most sunshine days is July (26.7 days).
The month with the least sunshine days is February (20.6 days).
Average UV index in September
Three Rivers, OR
- Average UV index in September: 3
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in September
Three Rivers, OR
- Average cloud cover in September: 17
The month with the most cloud cover is December (Cloud cover 46).
The months with the least cloud cover are July and August (Cloud cover 9).
Average visibility in September
Three Rivers, OR
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and December (5mi).
