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
September reports an average high-temperature of a still moderately hot 79.3°F (26.3°C), slightly varied from August's 84.6°F (29.2°C). In Swansea, September nights cool down to an average of 59.9°F (15.5°C).Humidity
In Swansea, the average relative humidity in September is 75%.Rainfall
In September, the rain falls for 12.5 days. Throughout September, 2.2" (56mm) of precipitation is accumulated. Throughout the year, there are 147.1 rainfall days, and 35.43" (900mm) of precipitation is accumulated.Snowfall
In Swansea, snow does not fall in April through October.Daylight
The average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:29 am and sunset at 7:29 pm. On the last day of September, sunrise is at 6:55 am and sunset at 6:43 pm CDT.
Sunshine
In Swansea, the average sunshine in September is 9.2h.UV index
In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The maximum UV index, 5 during September, leads to the following recommendations:
Preventative actions are necessary - Recommendations to ward off sunburn are given. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat. Take warning! The intensity of the Sun's UV radiation can be nearly amplified twice due to snow reflection.
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 many days does it rain in September in Swansea?
When it does not snow?
How many hours of daylight does Swansea have in September?
When are sunrise and sunset in September in Swansea?
How long on average sun shines in September?
What is the UV index intensity in September?
Average temperature in September
Swansea, IL
- Average high temperature in September: 79.3°F
The warmest month (with the highest average high temperature) is July (85.8°F).
The month with the lowest average high temperature is January (37.8°F).
- Average low temperature in September: 59.9°F
The month with the highest average low temperature is July (68.4°F).
The coldest month (with the lowest average low temperature) is January (24.8°F).
Average pressure in September
Swansea, IL
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Swansea, IL
- Average wind speed in September: 6.1mph
The windiest month (with the highest average wind speed) is January (9.4mph).
The calmest month (with the lowest average wind speed) is July (5.6mph).
Average humidity in September
Swansea, IL
- Average humidity in September: 75%
The months with the highest relative humidity are May and July (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Swansea, IL
- Average rainfall in September: 2.2"
The wettest month (with the highest rainfall) is May (4.37").
The driest month (with the least rainfall) is February (1.93").
Average rainfall days in September
Swansea, IL
- Average rainfall days in September: 12.5 days
The month with the highest number of rainy days is May (16.4 days).
The month with the least rainy days is January (6.8 days).
Average snowfall in September
Swansea, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.4").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Swansea, IL
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is January (7.3 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Swansea, IL
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 48min).
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 18min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).
Average sunshine days in September
Swansea, IL
- Average sunshine days in September: 16.1 days
The month with the most sunshine days is October (18.3 days).
The month with the least sunshine days is May (12.3 days).
Average UV index in September
Swansea, IL
- Average UV index in September: 5
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).
Average cloud cover in September
Swansea, IL
- Average cloud cover in September: 31
The month with the most cloud cover is January (Cloud cover 52).
The month with the least cloud cover is June (Cloud cover 29).
Average visibility in September
Swansea, 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).
Swansea, Illinois, USA
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