September weather forecastPrinceton, ID
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Princeton, Idaho, with an average temperature ranging between max 73.4°F (23°C) and min 51.4°F (10.8°C).Temperature
In Princeton, the beginning of September is marked by a lowered average high-temperature, shifting from August's 83.7°F (28.7°C) to a still moderately hot 73.4°F (23°C). In Princeton, the nighttime temperature registers a significant drop from daytime peaks to an average of 51.4°F (10.8°C) in September.Humidity
The average relative humidity in September is 48%.Rainfall
In Princeton, in September, during 8.1 rainfall days, 0.63" (16mm) of precipitation is typically accumulated. Throughout the year, in Princeton, there are 143.2 rainfall days, and 20.51" (521mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.28" (7mm) of snow. In Princeton, during the entire year, snow falls for 60.2 days and aggregates up to 47.24" (1200mm) of snow.Daylight
In Princeton, the average length of the day in September is 12h and 32min.On the first day of the month, sunrise is at 6:08 am and sunset at 7:26 pm. On the last day of September, in Princeton, sunrise is at 6:45 am and sunset at 6:28 pm PDT.
Sunshine
In Princeton, Idaho, the average sunshine in September is 10.3h.UV index
The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for the average person.Note: The daily high UV index of 4 in September translates into this advice:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. The midday Sun can be dangerous due to its intense radiation; always find shade and reduce exposure. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. On your guard! Snow's reflection can almost double the intensity of the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Princeton, ID
- Average high temperature in September: 73.4°F
The warmest month (with the highest average high temperature) is August (83.7°F).
The month with the lowest average high temperature is December (34°F).
- Average low temperature in September: 51.4°F
The month with the highest average low temperature is August (58.1°F).
The coldest month (with the lowest average low temperature) is December (24.1°F).
Average pressure in September
Princeton, ID
- Average pressure in September: 29.96"Hg
The month with the highest atmospheric pressure is January (30.2"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in September
Princeton, ID
- Average wind speed in September: 4.8mph
The windiest month (with the highest average wind speed) is April (6.3mph).
The calmest months (with the lowest average wind speed) are July, August and September (4.8mph).
Average humidity in September
Princeton, ID
- Average humidity in September: 48%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is August (40%).
Average rainfall in September
Princeton, ID
- Average rainfall in September: 0.63"
The wettest month (with the highest rainfall) is December (2.68").
The driest months (with the least rainfall) are July and August (0.47").
Average rainfall days in September
Princeton, ID
- Average rainfall days in September: 8.1 days
The month with the highest number of rainy days is April (18.1 days).
The months with the least rainy days are July and August (5.9 days).
Average snowfall in September
Princeton, ID
- Average snowfall in September: 0.28"
The month with the highest snowfall is January (12.56").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Princeton, ID
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is December (14.1 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Princeton, ID
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in September: 10h and 18min
The month with the most sunshine is August (Average sunshine: 12h and 0min).
The months with the least sunshine are January, February and December (Average sunshine: 4h and 30min).
Average sunshine days in September
Princeton, ID
- Average sunshine days in September: 20.1 days
The month with the most sunshine days is July (23.3 days).
The month with the least sunshine days is February (9.2 days).
Average UV index in September
Princeton, ID
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is February (UV index 1).
Average cloud cover in September
Princeton, ID
- Average cloud cover in September: 19
The month with the most cloud cover is February (Cloud cover 54).
The months with the least cloud cover are July and August (Cloud cover 12).
Average visibility in September
Princeton, ID
- Average visibility in September: 6mi
The months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and December (4mi).
