September weather forecastMilwaukee, WI

The modern Milwaukee City and Lake Michigan in Wisconsin, USA

September

Weather in September

With the advent of September, Milwaukee starts feeling the first whispers of autumn. There is a noticeable dip in temperature, complementing the changing hues of the city's foliage. The declining levels of humidity lend a crisper feel to the air. The least rainfall in September, recorded at 0.35" (9mm), underlines the calmness of the month. October ushers in more pronounced autumnal changes, with a noticeable shift in temperature and precipitation patterns.

Temperature

The onset of September aligns with a soft reduction in the average high-temperature, gently falling from a moderately hot 77°F (25°C) in August to an agreeable 70.5°F (21.4°C). During the nights in September, the temperature averages to a refreshing 57.4°F (14.1°C).

Humidity

The average relative humidity in September is 77%.

Rainfall

In September, the rain falls for 6.4 days. Throughout September, 0.35" (9mm) of precipitation is accumulated. In Milwaukee, during the entire year, the rain falls for 75.6 days and collects up to 5.83" (148mm) of precipitation.

Snowfall

In Milwaukee, snow does not fall in May through September.

Ocean temperature

In Milwaukee, the average seawater temperature in September is 66.9°F (19.4°C).
Note: The majority of people find swimming in 66.9°F (19.4°C) unenjoyable. As the water temperature decreases from 69.8°F (21°C) to 59°F (15°C), breathing becomes more challenging to control.

Daylight

In Milwaukee, the average length of the day in September is 12h and 29min.
On the first day of September, sunrise is at 6:16 am and sunset at 7:25 pm. On the last day of the month, sunrise is at 6:48 am and sunset at 6:34 pm CDT.

Sunshine

In Milwaukee, the average sunshine in September is 9.1h.

UV index

In Milwaukee, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the ordinary person.
Note: The UV index of 4 during September leads to these advisories:
Put precautions into practice - Guidance to elude sunburn is provided. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. Opt for tightly woven and loose clothing to enhance protection from the Sun.

Updated: Aug 1, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

In September, the average high-temperature and low-temperature are 70.5°F (21.4°C) and 57.4°F (14.1°C) respectively.

In September, the average relative humidity is 77%.

In Milwaukee, during September, the rain falls for 6.4 days and regularly aggregates up to 0.35" (9mm) of precipitation.

May through September are months without snowfall.

In Milwaukee, in September, it doesn't snow. In October, it regularly snows.

In September, the average ocean temperature is 66.9°F (19.4°C). Swimming in 66.9°F (19.4°C) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 69.8°F (21°C).

The average day length in September is 12h and 29min.

In September, on the first day of the month, sunrise is at 6:16 am and sunset at 7:25 pm. On the last day of the month, sunrise is at 6:48 am and sunset at 6:34 pm CDT.

In September, the average sunshine duration is 9.1h.

The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate vulnerability from unprotected exposure to UV radiation.

Today

Tomorrow

Long-term

Year J F M A M J J A September O N D

Aug

September

Oct

Average high temperature

77°F

70.5°F

57.4°F

Average low temperature

Average pressure

Average wind speed

Average max. wind speed

7.7mph

8.8mph

10.7mph

Average wind speed gusts

Average humidity

Average rainfall

Average rainfall days

Average snowfall

Average snowfall days

0.2

Average sea temperature

Average daylight

Average sunshine

Average sunshine days

20.1

21.8

22.1

Average UV index

Average cloud cover

Average visibility

Average temperature in September
Milwaukee, WI

Average high temperature in September: 70.5°F

The warmest month (with the highest average high temperature) is July (77.7°F).
The month with the lowest average high temperature is January (26.1°F).

Average low temperature in September: 57.4°F

The month with the highest average low temperature is July (64°F).
The coldest month (with the lowest average low temperature) is January (15.8°F).

Average pressure in September
Milwaukee, WI

Average pressure in September: 30.03"Hg

The months with the highest atmospheric pressure are January, February and March (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in September
Milwaukee, WI

Average wind speed in September: 8.5mph

The windiest month (with the highest average wind speed) is January (11.4mph).
The calmest month (with the lowest average wind speed) is July (7.1mph).

Average humidity in September
Milwaukee, WI

Average humidity in September: 77%

The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is October (75%).

Average rainfall in September
Milwaukee, WI

Average rainfall in September: 0.35"

The wettest month (with the highest rainfall) is July (0.75").
The driest months (with the least rainfall) are February and December (0.28").

Average rainfall days in September
Milwaukee, WI

Average rainfall days in September: 6.4 days

The month with the highest number of rainy days is June (9.9 days).
The months with the least rainy days are January and February (1.8 days).

Average snowfall in September
Milwaukee, WI

Average snowfall in September: 0"

The month with the highest snowfall is January (1.1").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Milwaukee, WI

Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (6.6 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average sea temperature in September
Milwaukee, WI

Average sea temperature in September: 66.9°F

The best month for swimming (with the highest average sea temperature) is August (71.9°F).
The coldest month (with the lowest average sea temperature) is February (36°F).

Average daylight in September /
Average sunshine in September
Milwaukee, WI

Average daylight in September: 12h and 30min

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 6min

The months with the most sunshine are July and August (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).

Average sunshine days in September
Milwaukee, WI

Average sunshine days in September: 21.8 days

The month with the most sunshine days is January (25.4 days).
The month with the least sunshine days is June (17.3 days).

Average UV index in September
Milwaukee, WI

Average UV index in September: 4

The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).

Average cloud cover in September
Milwaukee, WI

Average cloud cover in September: 30

The month with the most cloud cover is January (Cloud cover 63).
The months with the least cloud cover are July and August (Cloud cover 28).

Average visibility in September
Milwaukee, WI

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).