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 ushers in a slight temperature change, with average high-temperatures reducing from August's warm 77.5°F (25.3°C) to an agreeable 68.4°F (20.2°C). In September, the nighttime temperature plummets remarkably from the daily apex to a steady average of 43.2°F (6.2°C).Humidity
In Saint Charles, the average relative humidity in September is 48%.Rainfall
In Saint Charles, in September, it is raining for 9.5 days, with typically 1.14" (29mm) of accumulated precipitation. Throughout the year, there are 105.7 rainfall days, and 16.69" (424mm) of precipitation is accumulated.Snowfall
January through June, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.5 snowfall days, it receives 0.12" (3mm) of snow. Throughout the year, there are 104.6 snowfall days, and 63.58" (1615mm) of snow is accumulated.Daylight
The average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:51 am and sunset at 7:58 pm. On the last day of September, sunrise is at 7:22 am and sunset at 7:08 pm MDT.
Sunshine
In Saint Charles, the average sunshine in September is 10.1h.UV index
In Saint Charles, the average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for the average person.Note: During September, 3 as the daily maximum UV index converts into the following advice:
Put precautions into practice - Guidance to elude sunburn is provided. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays. Mind this! Nearly twice the UV radiation from the Sun can be reflected by the snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How much does it rain in September?
When does it start to snow?
How many hours of daylight does Saint Charles have in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
How high is the UV index in September?
Average temperature in September
Saint Charles, ID
- Average high temperature in September: 68.4°F
The warmest month (with the highest average high temperature) is July (79.2°F).
The month with the lowest average high temperature is December (25.5°F).
- Average low temperature in September: 43.2°F
The month with the highest average low temperature is August (49.8°F).
The coldest month (with the lowest average low temperature) is January (8.4°F).
Average pressure in September
Saint Charles, ID
- Average pressure in September: 29.97"Hg
The month with the highest atmospheric pressure is January (30.29"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Saint Charles, ID
- Average wind speed in September: 5.5mph
The windiest month (with the highest average wind speed) is June (6mph).
The calmest month (with the lowest average wind speed) is January (4.3mph).
Average humidity in September
Saint Charles, ID
- Average humidity in September: 48%
The month with the highest relative humidity is January (92%).
The month with the lowest relative humidity is August (42%).
Average rainfall in September
Saint Charles, ID
- Average rainfall in September: 1.14"
The wettest month (with the highest rainfall) is May (2.28").
The driest month (with the least rainfall) is July (0.91").
Average rainfall days in September
Saint Charles, ID
- Average rainfall days in September: 9.5 days
The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is January (4.3 days).
Average snowfall in September
Saint Charles, ID
- Average snowfall in September: 0.12"
The month with the highest snowfall is March (12.17").
The months with the least snowfall are July and August (0").
Average snowfall days in September
Saint Charles, ID
- Average snowfall days in September: 0.5 days
The month with the highest number of snowfall days is February (20 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Saint Charles, ID
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 10h and 1min
The months with the most sunshine are July and August (Average sunshine: 11h and 48min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).
Average sunshine days in September
Saint Charles, ID
- Average sunshine days in September: 17.5 days
The month with the most sunshine days is July (18.4 days).
The month with the least sunshine days is February (8.6 days).
Average UV index in September
Saint Charles, ID
- Average UV index in September: 3
The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, November and December (UV index 1).
Average cloud cover in September
Saint Charles, ID
- Average cloud cover in September: 17
The month with the most cloud cover is February (Cloud cover 63).
The months with the least cloud cover are July and August (Cloud cover 13).
Average visibility in September
Saint Charles, ID
- Average visibility in September: 6mi
The months with the highest visibility are May, June, July, August, September and October (6mi).
The months with the lowest visibility are January and February (3mi).
Saint Charles, Idaho, USA
Weather forecast for your location
2. Allow the app to use your location