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 shift from August to September coincides with a small decrease in the average high-temperature, down to a still warm 79.5°F (26.4°C) from 85.1°F (29.5°C). In the month of September, Waterloo records a consistent average low-temperature of 60.3°F (15.7°C).Humidity
The average relative humidity in September in Waterloo is 74%.Rainfall
In September, the rain falls for 11.9 days. Throughout September, 1.61" (41mm) of precipitation is accumulated. Throughout the year, there are 139.8 rainfall days, and 25.63" (651mm) of precipitation is accumulated.Snowfall
Months with snowfall in Waterloo are January through March, September, November and December. September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.04" (1mm) of snow. In Waterloo, during the entire year, snow falls for 18.7 days and aggregates up to 6.65" (169mm) of snow.Daylight
In September, the average length of the day in Waterloo is 12h and 25min.On the first day of the month, sunrise is at 6:30 am and sunset at 7:29 pm. On the last day of September, sunrise is at 6:56 am and sunset at 6:44 pm CDT.
Sunshine
In Waterloo, the average sunshine in September is 9.5h.UV index
In Waterloo, Illinois, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for the ordinary person.Note: A maximum high daily UV index of 5 during September translates into the following directions:
Take precautions - Protection against sunburn is recommended. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays. Bear in mind! The Sun's UV radiation can nearly double in intensity due to the reflective quality of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September in Waterloo?
What is the average humidity in September in Waterloo?
How much does it rain in Waterloo in September?
When does it start snowing in Waterloo?
What is the average length of the day in September in Waterloo?
When are sunrise and sunset in September in Waterloo?
How long on average sun shines in September in Waterloo?
What is the UV index reading in September in Waterloo?
Average temperature in September
Waterloo, IL
- Average high temperature in September: 79.5°F
The warmest month (with the highest average high temperature) is July (87.3°F).
The month with the lowest average high temperature is January (38.3°F).
- Average low temperature in September: 60.3°F
The month with the highest average low temperature is July (68.7°F).
The coldest month (with the lowest average low temperature) is January (25.2°F).
Average pressure in September
Waterloo, 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
Waterloo, IL
- Average wind speed in September: 5.8mph
The windiest month (with the highest average wind speed) is January (9.3mph).
The calmest months (with the lowest average wind speed) are July and August (5.5mph).
Average humidity in September
Waterloo, IL
- Average humidity in September: 74%
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Waterloo, IL
- Average rainfall in September: 1.61"
The wettest month (with the highest rainfall) is May (3.19").
The driest months (with the least rainfall) are February and November (1.34").
Average rainfall days in September
Waterloo, IL
- Average rainfall days in September: 11.9 days
The month with the highest number of rainy days is July (16.2 days).
The month with the least rainy days is January (6.3 days).
Average snowfall in September
Waterloo, IL
- Average snowfall in September: 0.04"
The month with the highest snowfall is January (1.89").
The months with the least snowfall are April, May, June, July, August and October (0").
Average snowfall days in September
Waterloo, IL
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is January (6.3 days).
The months with the least snowfall days are May, June, July, August and October (0 days).
Average daylight in September /
Average sunshine in September
Waterloo, 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 months with the most sunshine are June and July (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 42min).
Average sunshine days in September
Waterloo, IL
- Average sunshine days in September: 15.9 days
The month with the most sunshine days is January (20.6 days).
The month with the least sunshine days is July (12.5 days).
Average UV index in September
Waterloo, 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
Waterloo, IL
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 49).
The months with the least cloud cover are June and August (Cloud cover 27).
Average visibility in September
Waterloo, 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).
Waterloo, Illinois, USA
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