September weather forecast
Mason, IL

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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.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in Mason in September?

In Mason, in September, the average high-temperature is 77.5°F (25.3°C), and the average low-temperature is 59.4°F (15.2°C). The average heat index (a.k.a. 'feels like', 'real feel'), which represents the influence of relative humidity on air temperature, in August is computed to be 89.6°F (32°C).

What is the average humidity in September in Mason?

In Mason, the average relative humidity in September is 75%.

How much does it rain in Mason in September?

In Mason, Illinois, in September, it is raining for 10.8 days, with typically 1.54" (39mm) of accumulated precipitation.

When it does not snow in Mason?

April through October are months without snowfall in Mason.

How many hours of daylight does Mason have in September?

The average day length in September in Mason is 12h and 26min.

When is the sunrise / sunset in September in Mason?

In September, on the first day of the month, sunrise is at 6:24 am and sunset at 7:24 pm. On the last day of the month, in Mason, Illinois, sunrise is at 6:50 am and sunset at 6:38 pm CDT.

How long on average sun shines in September in Mason?

In September, the average sunshine duration is 9.2h.

What is the UV index intensity in September in Mason?

In September, the average daily maximum UV index in Mason, Illinois, is 5. A UV Index reading of 3 to 5 represents a medium hazard to health from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Mason, IL

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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 / Average sunshine in September - Mason, IL
  • Average daylight in September: 12h and 2min

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 1min

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 - 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 - 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 - 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 - 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).

Mason, Illinois, USA

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