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 move into September indicates a slight reduction in the average high-temperature, down from August's moderately hot 75.2°F (24°C) to a refreshing 66.9°F (19.4°C). Mercer temperatures generally rest at a low of 48.9°F (9.4°C) during the September nights.Humidity
The average relative humidity in September in Mercer is 79%.Rainfall
In Mercer, during September, the rain falls for 13.8 days and regularly aggregates up to 1.61" (41mm) of precipitation. In Mercer, during the entire year, the rain falls for 126.3 days and collects up to 24.09" (612mm) of precipitation.Snowfall
June through September are months without snowfall.Daylight
The average length of the day in September is 12h and 32min.On the first day of September, sunrise is at 6:21 am and sunset at 7:38 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 6:41 pm CDT.
Sunshine
The average sunshine in September is 7.9h.UV index
In September, the average daily maximum UV index is 3. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for average individuals.Note: In September, a daily UV index of 3 turns into the following recommendations:
Undertake protective steps - Recommendations to avoid sunburn are issued. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September in Mercer?
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 in Mercer?
When are sunrise and sunset in September?
How many hours of sunshine does Mercer have in September?
How high is the UV index in September?
Average temperature in September
Mercer, WI
- Average high temperature in September: 66.9°F
The warmest month (with the highest average high temperature) is July (77.5°F).
The month with the lowest average high temperature is January (18.3°F).
- Average low temperature in September: 48.9°F
The month with the highest average low temperature is July (56.8°F).
The coldest month (with the lowest average low temperature) is January (7°F).
Average pressure in September
Mercer, WI
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is February (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Mercer, WI
- Average wind speed in September: 7.6mph
The windiest month (with the highest average wind speed) is November (8.8mph).
The calmest month (with the lowest average wind speed) is August (6.8mph).
Average humidity in September
Mercer, WI
- Average humidity in September: 79%
The month with the highest relative humidity is January (93%).
The month with the lowest relative humidity is May (71%).
Average rainfall in September
Mercer, WI
- Average rainfall in September: 1.61"
The wettest month (with the highest rainfall) is May (3.15").
The driest month (with the least rainfall) is January (1.26").
Average rainfall days in September
Mercer, WI
- Average rainfall days in September: 13.8 days
The months with the highest number of rainy days are May and June (16 days).
The month with the least rainy days is January (3 days).
Average snowfall in September
Mercer, WI
- Average snowfall in September: 0"
The month with the highest snowfall is December (10.75").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Mercer, WI
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (25.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Mercer, WI
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 42min).
The month with the shortest days is December (Average daylight: 8h and 42min).
- Average sunshine in September: 7h and 5min
The month with the most sunshine is July (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 1h and 54min).
Average sunshine days in September
Mercer, WI
- Average sunshine days in September: 13.7 days
The month with the most sunshine days is August (14.3 days).
The month with the least sunshine days is January (6.3 days).
Average UV index in September
Mercer, WI
- Average UV index in September: 3
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 1).
Average cloud cover in September
Mercer, WI
- Average cloud cover in September: 43
The month with the most cloud cover is January (Cloud cover 82).
The month with the least cloud cover is July (Cloud cover 37).
Average visibility in September
Mercer, WI
- Average visibility in September: 5mi
The months with the highest visibility are May and June (6mi).
The months with the lowest visibility are January, February and December (4mi).
Mercer, Wisconsin, USA
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