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
The onset of September aligns with a soft reduction in the average high-temperature, gently falling from 83.7°F (28.7°C) in August to a still moderately hot 78.1°F (25.6°C). An average low-temperature of 59.7°F (15.4°C) is noted during the nights in September.Humidity
In Saint Jacob, the average relative humidity in September is 75%.Rainfall
In September, the rain falls for 9.5 days. Throughout September, 0.59" (15mm) of precipitation is accumulated. Throughout the year, there are 110.6 rainfall days, and 12.01" (305mm) of precipitation is accumulated.Snowfall
April through September are months without snowfall.Daylight
In Saint Jacob, the average length of the day in September is 12h and 26min.On the first day of September, sunrise is at 6:28 am and sunset at 7:28 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 6:42 pm CDT.
Sunshine
In Saint Jacob, the average sunshine in September is 9.5h.UV index
In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the average person.Note: In September, the average maximum UV index of 5 translates into the following recommendations:
Be vigilant - Preventing sunburn is recommended. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
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 Saint Jacob have in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
What is the UV index reading in September in Saint Jacob?
Average temperature in September
Saint Jacob, IL
- Average high temperature in September: 78.1°F
The warmest month (with the highest average high temperature) is July (84.9°F).
The month with the lowest average high temperature is January (36.9°F).
- Average low temperature in September: 59.7°F
The month with the highest average low temperature is July (67.6°F).
The coldest month (with the lowest average low temperature) is January (23.7°F).
Average pressure in September
Saint Jacob, 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
Saint Jacob, IL
- Average wind speed in September: 6.2mph
The windiest month (with the highest average wind speed) is January (9.8mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).
Average humidity in September
Saint Jacob, IL
- Average humidity in September: 75%
The months with the highest relative humidity are July and August (80%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Saint Jacob, IL
- Average rainfall in September: 0.59"
The wettest month (with the highest rainfall) is May (1.46").
The driest month (with the least rainfall) is February (0.55").
Average rainfall days in September
Saint Jacob, IL
- Average rainfall days in September: 9.5 days
The month with the highest number of rainy days is May (13.1 days).
The months with the least rainy days are January and December (5.9 days).
Average snowfall in September
Saint Jacob, IL
- Average snowfall in September: 0"
The month with the highest snowfall is December (0.94").
The months with the least snowfall are April, May, June, July, August and September (0").
Average snowfall days in September
Saint Jacob, IL
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and February (4.8 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Saint Jacob, 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 3min
The month with the most sunshine is June (Average sunshine: 10h and 36min).
The months with the least sunshine are January and February (Average sunshine: 4h and 36min).
Average sunshine days in September
Saint Jacob, IL
- Average sunshine days in September: 18.3 days
The month with the most sunshine days is December (21.8 days).
The month with the least sunshine days is July (14.5 days).
Average UV index in September
Saint Jacob, 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, November and December (UV index 2).
Average cloud cover in September
Saint Jacob, IL
- Average cloud cover in September: 28
The months with the most cloud cover are January and February (Cloud cover 50).
The months with the least cloud cover are June, July, August and September (Cloud cover 28).
Average visibility in September
Saint Jacob, 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).
Saint Jacob, Illinois, USA
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