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 transition into September involves a decrease in the average high-temperature, falling from a warm 75.7°F (24.3°C) in August to a comfortable 65.8°F (18.8°C). Nighttime temperatures throughout September register a significant deviation from the day's highs, averaging at a wintry 40.1°F (4.5°C).Humidity
In Flat Rock, Idaho, the average relative humidity in September is 53%.Rainfall
In Flat Rock, during September, the rain falls for 7.9 days and regularly aggregates up to 1.14" (29mm) of precipitation. In Flat Rock, during the entire year, the rain falls for 106.1 days and collects up to 20.83" (529mm) of precipitation.Snowfall
Months with snowfall are January through July, September through December. September is the first month it typically snows. Throughout September, in the average 1.2 snowfall days, it receives 1.69" (43mm) of snow. Throughout the year, there are 138.1 snowfall days, and 107.64" (2734mm) of snow is accumulated.Daylight
In September, the average length of the day is 12h and 30min.On the first day of the month, sunrise is at 6:48 am and sunset at 8:01 pm. On the last day of September, sunrise is at 7:22 am and sunset at 7:07 pm MDT.
Sunshine
In September, the average sunshine is 9.9h.UV index
The average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for the average person.Note: In September, the maximum UV index of 3 suggests this advice:
Prioritize safety - Recommendations to avert sunburn are shared. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Warning! The reflection from snow can nearly magnify the Sun's UV radiation twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature?
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 are sunrise and sunset in September?
How long on average sun shines in September?
How high is the UV index in September in Flat Rock?
Average temperature in September
Flat Rock, ID
- Average high temperature in September: 65.8°F
The warmest month (with the highest average high temperature) is July (77.4°F).
The month with the lowest average high temperature is December (22.3°F).
- Average low temperature in September: 40.1°F
The month with the highest average low temperature is August (46.6°F).
The coldest months (with the lowest average low temperature) are January and December (6.8°F).
Average pressure in September
Flat Rock, ID
- Average pressure in September: 29.99"Hg
The month with the highest atmospheric pressure is January (30.26"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Flat Rock, ID
- Average wind speed in September: 5.5mph
The windiest month (with the highest average wind speed) is June (6.3mph).
The calmest month (with the lowest average wind speed) is January (4.4mph).
Average humidity in September
Flat Rock, ID
- Average humidity in September: 53%
The months with the highest relative humidity are January and February (94%).
The month with the lowest relative humidity is August (47%).
Average rainfall in September
Flat Rock, ID
- Average rainfall in September: 1.14"
The wettest month (with the highest rainfall) is February (2.64").
The driest month (with the least rainfall) is July (0.47").
Average rainfall days in September
Flat Rock, ID
- Average rainfall days in September: 7.9 days
The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is January (3.8 days).
Average snowfall in September
Flat Rock, ID
- Average snowfall in September: 1.69"
The month with the highest snowfall is January (19.84").
The month with the least snowfall is August (0").
Average snowfall days in September
Flat Rock, ID
- Average snowfall days in September: 1.2 days
The month with the highest number of snowfall days is December (23 days).
The month with the least snowfall days is August (0 days).
Average daylight in September /
Average sunshine in September
Flat Rock, ID
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in September: 9h and 5min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).
Average sunshine days in September
Flat Rock, ID
- Average sunshine days in September: 19.3 days
The month with the most sunshine days is July (21.2 days).
The month with the least sunshine days is February (5.9 days).
Average UV index in September
Flat Rock, 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, February, November and December (UV index 1).
Average cloud cover in September
Flat Rock, ID
- Average cloud cover in September: 19
The month with the most cloud cover is February (Cloud cover 67).
The month with the least cloud cover is July (Cloud cover 13).
Average visibility in September
Flat Rock, 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, February and December (3mi).
Flat Rock, Idaho, USA
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