September weather forecastHarristown, IL
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Harristown, Illinois, with an average temperature fluctuating between 77°F (25°C) and 58.5°F (14.7°C).Temperature
The beginning of September records an average high-temperature of a still warm 77°F (25°C), marking a negligible difference from August's 81.1°F (27.3°C). In September, Harristown records an average nighttime temperature of 58.5°F (14.7°C).Humidity
The average relative humidity in September is 76%.Rainfall
In Harristown, during September, the rain falls for 10.6 days and regularly aggregates up to 1.18" (30mm) of precipitation. In Harristown, during the entire year, the rain falls for 130.2 days and collects up to 16.34" (415mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
The average length of the day in September is 12h and 26min.On the first day of September, sunrise is at 6:25 am and sunset at 7:27 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:39 pm CDT.
Sunshine
In Harristown, the average sunshine in September is 9.2h.UV index
In Harristown, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: The daily high UV index of 5 during September translates into the following recommendations:
Heed the precautions - It is counselled to guard against solar damage. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Harristown, IL
- Average high temperature in September: 77°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (32.9°F).
- Average low temperature in September: 58.5°F
The month with the highest average low temperature is July (65.7°F).
The coldest month (with the lowest average low temperature) is January (21.2°F).
Average pressure in September
Harristown, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Harristown, IL
- Average wind speed in September: 7.2mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (6.3mph).
Average humidity in September
Harristown, IL
- Average humidity in September: 76%
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (70%).
Average rainfall in September
Harristown, IL
- Average rainfall in September: 1.18"
The wettest month (with the highest rainfall) is May (2.01").
The driest months (with the least rainfall) are February and December (0.87").
Average rainfall days in September
Harristown, IL
- Average rainfall days in September: 10.6 days
The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is February (5.8 days).
Average snowfall in September
Harristown, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (1.85").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Harristown, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (7.2 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
Harristown, IL
- Average daylight in September: 12h and 24min
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: 9h and 12min
The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in September
Harristown, IL
- Average sunshine days in September: 17.3 days
The month with the most sunshine days is October (19.8 days).
The month with the least sunshine days is May (11.5 days).
Average UV index in September
Harristown, 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
Harristown, IL
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is September (Cloud cover 29).
Average visibility in September
Harristown, IL
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
