September weather forecastMason, IL
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Mason, Illinois, with temperature in the range of an average low of 59.4°F (15.2°C) and an average high of 77.5°F (25.3°C).Temperature
The advent of September signifies a minor shift to an average high-temperature of a still moderately hot 77.5°F (25.3°C), aligning closely with August. During September, Mason experiences an average low-temperature of 59.4°F (15.2°C) at night.Humidity
The average relative humidity in September is 75%.Rainfall
In September, in Mason, the rain falls for 10.8 days. Throughout September, 1.54" (39mm) of precipitation is accumulated. In Mason, during the entire year, the rain falls for 141.3 days and collects up to 26.77" (680mm) of precipitation.Snowfall
In Mason, Illinois, snow does not fall in April through October.Daylight
In Mason, the average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 6:24 am and sunset at 7:24 pm. On the last day of September, sunrise is at 6:50 am and sunset at 6:38 pm CDT.
Sunshine
In September, the average sunshine is 9.2h.UV index
In Mason, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for the ordinary person.Note: A maximum high daily UV index of 5 during September translates into the following directions:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. It's recommended to limit sun exposure when its radiation is at its peak during midday. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Mason, IL
- Average high temperature in September: 77.5°F
The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (35.6°F).
- Average low temperature in September: 59.4°F
The month with the highest average low temperature is July (67.1°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).
Average pressure in September
Mason, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Mason, IL
- Average wind speed in September: 6.7mph
The windiest months (with the highest average wind speed) are January and February (10.3mph).
The calmest months (with the lowest average wind speed) are July and August (6mph).
Average humidity in September
Mason, IL
- Average humidity in September: 75%
The months with the highest relative humidity are July and August (81%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Mason, IL
- Average rainfall in September: 1.54"
The wettest month (with the highest rainfall) is April (3.35").
The driest month (with the least rainfall) is February (1.38").
Average rainfall days in September
Mason, IL
- Average rainfall days in September: 10.8 days
The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is January (7.3 days).
Average snowfall in September
Mason, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.01").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Mason, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (5.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Mason, IL
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 9h and 12min
The month with the most sunshine is June (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).
Average sunshine days in September
Mason, IL
- Average sunshine days in September: 17.1 days
The month with the most sunshine days is December (19.5 days).
The month with the least sunshine days is May (10.8 days).
Average UV index in September
Mason, IL
- Average UV index in September: 5
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, November and December (UV index 2).
Average cloud cover in September
Mason, IL
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 53).
The months with the least cloud cover are June and September (Cloud cover 29).
Average visibility in September
Mason, IL
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
