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 is characterized by a mild reduction in the average high-temperature, from a moderately hot 78.3°F (25.7°C) in August to an agreeable 72.9°F (22.7°C). The mean low-temperature during September nights is a fresh 54°F (12.2°C).Humidity
In Janesville, the average relative humidity in September is 78%.Rainfall
In September, the rain falls for 12.8 days. Throughout September, 2.4" (61mm) of precipitation is accumulated. In Janesville, during the entire year, the rain falls for 138.7 days and collects up to 28.78" (731mm) of precipitation.Snowfall
June through September are months without snowfall.Daylight
In Janesville, the average length of the day in September is 12h and 29min.On the first day of the month, sunrise is at 6:35 am and sunset at 7:43 pm. On the last day of September, sunrise is at 7:06 am and sunset at 6:52 pm CDT.
Sunshine
The average sunshine in September is 9.1h.UV index
In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for ordinary individuals.Note: An average maximum UV index of 4 in September leads to these recommendations:
Take heed. Individuals of lighter complexion can be burned in less than half an hour. To guard against the harmful effects of the Sun, minimize exposure during midday. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Janesville in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Janesville have in September?
What is the UV index reading in September?
Average temperature in September
Janesville, IA
- Average high temperature in September: 72.9°F
The warmest month (with the highest average high temperature) is July (79.5°F).
The month with the lowest average high temperature is January (23.9°F).
- Average low temperature in September: 54°F
The month with the highest average low temperature is July (63°F).
The coldest month (with the lowest average low temperature) is January (11.3°F).
Average pressure in September
Janesville, IA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in September
Janesville, IA
- Average wind speed in September: 8.2mph
The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest month (with the lowest average wind speed) is August (7mph).
Average humidity in September
Janesville, IA
- Average humidity in September: 78%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Janesville, IA
- Average rainfall in September: 2.4"
The wettest month (with the highest rainfall) is June (4.29").
The driest month (with the least rainfall) is January (1.02").
Average rainfall days in September
Janesville, IA
- Average rainfall days in September: 12.8 days
The month with the highest number of rainy days is June (19.4 days).
The month with the least rainy days is February (3.9 days).
Average snowfall in September
Janesville, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (5.08").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Janesville, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Janesville, IA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 9h and 1min
The month with the most sunshine is July (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).
Average sunshine days in September
Janesville, IA
- Average sunshine days in September: 15.5 days
The months with the most sunshine days are October and November (17.8 days).
The month with the least sunshine days is June (9.2 days).
Average UV index in September
Janesville, IA
- Average UV index in September: 4
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Janesville, IA
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 31).
Average visibility in September
Janesville, IA
- 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).
Janesville, Iowa, USA
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