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
As September commences, the average high-temperature subtly reduces, transitioning from 80.1°F (26.7°C) in August to a still moderately hot 74.5°F (23.6°C). River Forest, in September, witnesses an average low-temperature of 57.4°F (14.1°C).Humidity
In River Forest, Indiana, the average relative humidity in September is 78%.Rainfall
In River Forest, during September, the rain falls for 12.4 days and regularly aggregates up to 1.38" (35mm) of precipitation. Throughout the year, there are 142.1 rainfall days, and 20.91" (531mm) of precipitation is accumulated.Snowfall
In River Forest, snow does not fall in May through September.Daylight
In River Forest, the average length of the day in September is 12h and 26min.On the first day of September, sunrise is at 7:11 am and sunset at 8:14 pm. On the last day of the month, sunrise is at 7:38 am and sunset at 7:26 pm EDT.
Sunshine
The average sunshine in September is 8.2h.UV index
In River Forest, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from unsafe exposure to UV radiation for average individuals.Note: The maximum UV index of 4 during September translates into these guidelines:
Guard yourself - Avoiding sunburn is suggested. The Sun's harshest UV rays are around midday; it's wise to seek shade and limit time outdoors. Enhance your sun protection with tightly woven, yet airy clothing.
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 many days does it rain in September?
When it does not snow?
Does it snow in September?
How many hours of daylight does River Forest have in September?
What time 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
River Forest, IN
- Average high temperature in September: 74.5°F
The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (32.2°F).
- Average low temperature in September: 57.4°F
The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (20.5°F).
Average pressure in September
River Forest, IN
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
River Forest, IN
- Average wind speed in September: 6.7mph
The windiest month (with the highest average wind speed) is January (10.3mph).
The calmest month (with the lowest average wind speed) is August (5.9mph).
Average humidity in September
River Forest, IN
- Average humidity in September: 78%
The months with the highest relative humidity are January and December (83%).
The month with the lowest relative humidity is October (74%).
Average rainfall in September
River Forest, IN
- Average rainfall in September: 1.38"
The wettest month (with the highest rainfall) is May (2.68").
The driest months (with the least rainfall) are February and November (1.14").
Average rainfall days in September
River Forest, IN
- Average rainfall days in September: 12.4 days
The month with the highest number of rainy days is May (17.6 days).
The month with the least rainy days is February (6.1 days).
Average snowfall in September
River Forest, IN
- Average snowfall in September: 0"
The months with the highest snowfall are February and December (2.17").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
River Forest, IN
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.4 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
River Forest, IN
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 8h and 1min
The month with the most sunshine is June (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
River Forest, IN
- Average sunshine days in September: 15 days
The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is May (10.7 days).
Average UV index in September
River Forest, IN
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in September
River Forest, IN
- Average cloud cover in September: 34
The month with the most cloud cover is January (Cloud cover 62).
The months with the least cloud cover are June, July and August (Cloud cover 32).
Average visibility in September
River Forest, IN
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, September, October, November and December (6mi).
The month with the lowest visibility is August (5mi).
River Forest, Indiana, USA
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