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
The start of September involves a temperature drop, moving from a moderately hot 83.3°F (28.5°C) in August to an agreeable 72.9°F (22.7°C). Shelley reports a considerable drop from daytime temperatures in September, recording an average nighttime figure of 49.3°F (9.6°C).Humidity
In Shelley, the average relative humidity in September is 41%.Rainfall
In Shelley, during September, the rain falls for 10.1 days and regularly aggregates up to 1.06" (27mm) of precipitation. Throughout the year, there are 124.6 rainfall days, and 12.24" (311mm) 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 0.1 snowfall days, it receives 0.2" (5mm) of snow. Throughout the year, there are 75.1 snowfall days, and 30.59" (777mm) of snow is accumulated.Daylight
The average length of the day in September is 12h and 29min.On the first day of September, sunrise is at 6:53 am and sunset at 8:03 pm. On the last day of the month, sunrise is at 7:25 am and sunset at 7:10 pm MDT.
Sunshine
In September, the average sunshine is 9.9h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: The maximum UV index, 4 during September, leads to the following recommendations:
Put precautions into practice - Guidance to elude sunburn is provided. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim. Be aware! The reflective nature of snow can magnify the Sun's UV radiation almost twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
What is the average humidity in September?
How many days does it rain in September?
When does it start snowing?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Shelley have in September?
What is the UV index intensity in September?
Average temperature in September
Shelley, ID
- Average high temperature in September: 72.9°F
The warmest month (with the highest average high temperature) is July (85.3°F).
The month with the lowest average high temperature is December (27.9°F).
- Average low temperature in September: 49.3°F
The month with the highest average low temperature is August (55°F).
The coldest month (with the lowest average low temperature) is January (14.7°F).
Average pressure in September
Shelley, ID
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.3"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Shelley, ID
- Average wind speed in September: 7.5mph
The windiest month (with the highest average wind speed) is April (8.9mph).
The calmest month (with the lowest average wind speed) is January (6mph).
Average humidity in September
Shelley, ID
- Average humidity in September: 41%
The month with the highest relative humidity is January (90%).
The months with the lowest relative humidity are July and August (36%).
Average rainfall in September
Shelley, ID
- Average rainfall in September: 1.06"
The wettest month (with the highest rainfall) is May (1.57").
The driest month (with the least rainfall) is July (0.51").
Average rainfall days in September
Shelley, ID
- Average rainfall days in September: 10.1 days
The month with the highest number of rainy days is May (15.9 days).
The month with the least rainy days is January (6.1 days).
Average snowfall in September
Shelley, ID
- Average snowfall in September: 0.2"
The month with the highest snowfall is January (7.44").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Shelley, ID
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is December (16.7 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Shelley, ID
- Average daylight in September: 12h and 3min
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: 9h and 5min
The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 4h and 48min).
Average sunshine days in September
Shelley, ID
- Average sunshine days in September: 17.3 days
The month with the most sunshine days is October (18.9 days).
The month with the least sunshine days is March (10 days).
Average UV index in September
Shelley, ID
- 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 and December (UV index 1).
Average cloud cover in September
Shelley, ID
- Average cloud cover in September: 16
The month with the most cloud cover is February (Cloud cover 51).
The months with the least cloud cover are July and August (Cloud cover 11).
Average visibility in September
Shelley, 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 February (4mi).
Shelley, Idaho, USA
Weather forecast for your location
2. Allow the app to use your location