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's onset corresponds with a shift in the average high-temperature, moving from a moderately hot 82.9°F (28.3°C) in August to an agreeable 72.5°F (22.5°C). With a significant temperature contrast, nighttime temperatures hover around an average low of 47.1°F (8.4°C) in September.Humidity
In September, the average relative humidity in Chester is 44%.Rainfall
In Chester, in September, it is raining for 7.1 days, with typically 0.87" (22mm) of accumulated precipitation. Throughout the year, there are 97.5 rainfall days, and 11.85" (301mm) 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 0.04" (1mm) of snow. In Chester, during the entire year, snow falls for 83.8 days and aggregates up to 41.93" (1065mm) of snow.Daylight
In Chester, the average length of the day in September is 12h and 29min.On the first day of the month, sunrise is at 6:50 am and sunset at 8:01 pm. On the last day of September, in Chester, sunrise is at 7:23 am and sunset at 7:08 pm MDT.
Sunshine
In Chester, the average sunshine in September is 10h.UV index
The average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The maximum daily UV index of 4 in September converts into the following recommendations:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. Boost your sun resistance with garments that are densely woven yet spacious. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the average humidity in September?
How much does it rain in September?
When does it start to snow?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How long on average sun shines in September?
What is the UV index reading in September in Chester?
Average temperature in September
Chester, ID
- Average high temperature in September: 72.5°F
The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is December (26.2°F).
- Average low temperature in September: 47.1°F
The month with the highest average low temperature is August (52.5°F).
The coldest month (with the lowest average low temperature) is January (12.4°F).
Average pressure in September
Chester, ID
- Average pressure in September: 29.99"Hg
The month with the highest atmospheric pressure is January (30.28"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Chester, ID
- Average wind speed in September: 6.2mph
The windiest month (with the highest average wind speed) is June (6.9mph).
The calmest month (with the lowest average wind speed) is January (4.2mph).
Average humidity in September
Chester, ID
- Average humidity in September: 44%
The month with the highest relative humidity is January (91%).
The month with the lowest relative humidity is August (39%).
Average rainfall in September
Chester, ID
- Average rainfall in September: 0.87"
The wettest month (with the highest rainfall) is January (1.5").
The driest month (with the least rainfall) is July (0.28").
Average rainfall days in September
Chester, ID
- Average rainfall days in September: 7.1 days
The month with the highest number of rainy days is April (13 days).
The month with the least rainy days is July (5 days).
Average snowfall in September
Chester, ID
- Average snowfall in September: 0.04"
The month with the highest snowfall is January (11.97").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Chester, ID
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is January (18.1 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Chester, 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: 10h and 0min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).
Average sunshine days in September
Chester, ID
- Average sunshine days in September: 20.7 days
The month with the most sunshine days is July (24.8 days).
The month with the least sunshine days is February (10.6 days).
Average UV index in September
Chester, 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, February, November and December (UV index 1).
Average cloud cover in September
Chester, ID
- Average cloud cover in September: 16
The month with the most cloud cover is February (Cloud cover 56).
The months with the least cloud cover are July and August (Cloud cover 11).
Average visibility in September
Chester, ID
- Average visibility in September: 6mi
The months with the highest visibility are April, May, June, July, August, September, October and November (6mi).
The month with the lowest visibility is January (3mi).
Chester, Idaho, USA
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