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 arrival of September brings an average high-temperature of a still moderately hot 74.7°F (23.7°C), nearly identical to August's 79.5°F (26.4°C). During the nights in September, an average low-temperature of 56.3°F (13.5°C) is observed.Humidity
In Seneca, the average relative humidity in September is 78%.Rainfall
In Seneca, in September, it is raining for 12.3 days, with typically 2.32" (59mm) of accumulated precipitation. Throughout the year, there are 154.1 rainfall days, and 31.73" (806mm) of precipitation is accumulated.Snowfall
In Seneca, Illinois, snow does not fall in May through September.Daylight
In Seneca, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:21 am and sunset at 7:26 pm. On the last day of September, in Seneca, sunrise is at 6:50 am and sunset at 6:37 pm CDT.
Sunshine
In September, the average sunshine in Seneca is 8.9h.UV index
In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for the average person.Note: The daily high UV index of 4 in September translates into this advice:
Guard yourself - Precautionary measures against sun damage are advocated. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. Arm yourself against UV rays' harm with protective apparel and UV-filtering shades.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature in Seneca?
What is the average humidity in September in Seneca?
How much does it rain in Seneca in September?
When it does not snow in Seneca?
Does it snow in Seneca in September?
How many hours of daylight does Seneca have in September?
When are sunrise and sunset in September in Seneca?
How many hours of sunshine does Seneca have in September?
What is the UV index intensity in September in Seneca?
Average temperature in September
Seneca, IL
- Average high temperature in September: 74.7°F
The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (29.1°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (17.2°F).
Average pressure in September
Seneca, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Seneca, IL
- Average wind speed in September: 7.3mph
The windiest months (with the highest average wind speed) are January and April (10.1mph).
The calmest month (with the lowest average wind speed) is August (6.1mph).
Average humidity in September
Seneca, IL
- Average humidity in September: 78%
The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Seneca, IL
- Average rainfall in September: 2.32"
The wettest month (with the highest rainfall) is May (4.49").
The driest month (with the least rainfall) is December (1.65").
Average rainfall days in September
Seneca, IL
- Average rainfall days in September: 12.3 days
The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is February (5.8 days).
Average snowfall in September
Seneca, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (4.57").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Seneca, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.9 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
Seneca, IL
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 8h and 5min
The months with the most sunshine are June and August (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in September
Seneca, IL
- Average sunshine days in September: 15.1 days
The month with the most sunshine days is November (17.1 days).
The month with the least sunshine days is June (10.1 days).
Average UV index in September
Seneca, IL
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
Seneca, IL
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 59).
The month with the least cloud cover is September (Cloud cover 32).
Average visibility in September
Seneca, IL
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).
Seneca, Illinois, USA
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