September weather forecast
Winthrop Harbor, IL

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Weather in September

The first month of the autumn, September, is still a pleasant month in Winthrop Harbor, Illinois, with an average temperature fluctuating between 58.5°F (14.7°C) and 70.9°F (21.6°C).

Temperature

In September, the average high-temperature marginally drops from a warm 77°F (25°C) in August to a pleasant 70.9°F (21.6°C). Winthrop Harbor's temperature tends to fall to an average low of 58.5°F (14.7°C) during the nights of September.

Humidity

In September, the average relative humidity in Winthrop Harbor is 77%.

Rainfall

In Winthrop Harbor, in September, it is raining for 12.7 days, with typically 1.73" (44mm) of accumulated precipitation. In Winthrop Harbor, during the entire year, the rain falls for 142.5 days and collects up to 21.5" (546mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

The average length of the day in September in Winthrop Harbor is 12h and 28min.
On the first day of the month, sunrise is at 6:17 am and sunset at 7:24 pm. On the last day of September, sunrise is at 6:48 am and sunset at 6:33 pm CDT.

Sunshine

The average sunshine in September in Winthrop Harbor, Illinois, is 9.2h.

UV index

In September, the average daily maximum UV index in Winthrop Harbor, Illinois, is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for the average person.
Note: The daily high UV index of 4 in September translates into this advice:
Guard yourself - Avoiding sunburn is suggested. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature in Winthrop Harbor?

In Winthrop Harbor, in September, the average high-temperature is 70.9°F (21.6°C), and the average low-temperature is 58.5°F (14.7°C).

What is the average humidity in September in Winthrop Harbor?

The average relative humidity in September in Winthrop Harbor is 77%.

How much does it rain in Winthrop Harbor in September?

In Winthrop Harbor, in September, during 12.7 rainfall days, 1.73" (44mm) of precipitation is typically accumulated.

When it does not snow in Winthrop Harbor?

In Winthrop Harbor, snow does not fall in May through September.

Does it snow in Winthrop Harbor in September?

In Winthrop Harbor, Illinois, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September in Winthrop Harbor?

The average day length in September in Winthrop Harbor is 12h and 28min.

What time are sunrise and sunset in September in Winthrop Harbor?

In September, on the first day of the month, sunrise is at 6:17 am and sunset at 7:24 pm. On the last day of the month, in Winthrop Harbor, Illinois, sunrise is at 6:48 am and sunset at 6:33 pm CDT.

How many hours of sunshine does Winthrop Harbor have in September?

In Winthrop Harbor, Illinois, the average sunshine duration in September is 9.2h.

What is the UV index intensity in September in Winthrop Harbor?

In Winthrop Harbor, Illinois, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Winthrop Harbor, IL

Average temperature in September - Winthrop Harbor, IL
  • Average high temperature in September: 70.9°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 (27.9°F).

  • Average low temperature in September: 58.5°F

The month with the highest average low temperature is July (65.3°F).
The coldest month (with the lowest average low temperature) is January (18.3°F).

Average pressure in September
Winthrop Harbor, IL

Average pressure in September - Winthrop Harbor, IL
  • Average pressure in September: 30.03"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in September
Winthrop Harbor, IL

Average wind speed in September - Winthrop Harbor, IL
  • Average wind speed in September: 8.8mph

The windiest month (with the highest average wind speed) is January (11.9mph).
The calmest month (with the lowest average wind speed) is August (7.3mph).

Average humidity in September
Winthrop Harbor, IL

Average humidity in September - Winthrop Harbor, IL
  • Average humidity in September: 77%

The month with the highest relative humidity is January (83%).
The months with the lowest relative humidity are October and November (75%).

Average rainfall in September
Winthrop Harbor, IL

Average rainfall in September - Winthrop Harbor, IL
  • Average rainfall in September: 1.73"

The wettest months (with the highest rainfall) are June and August (2.68").
The driest month (with the least rainfall) is December (0.91").

Average rainfall days in September
Winthrop Harbor, IL

Average rainfall days in September - Winthrop Harbor, IL
  • Average rainfall days in September: 12.7 days

The month with the highest number of rainy days is July (17 days).
The month with the least rainy days is February (5.2 days).

Average snowfall in September
Winthrop Harbor, IL

Average snowfall in September - Winthrop Harbor, IL
  • Average snowfall in September: 0"

The month with the highest snowfall is February (2.6").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Winthrop Harbor, IL

Average snowfall days in September - Winthrop Harbor, IL
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (12.4 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Winthrop Harbor, IL

Average daylight in September / Average sunshine in September - Winthrop Harbor, IL
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 6min).

  • Average sunshine in September: 9h and 1min

The months with the most sunshine are July and August (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

Average sunshine days in September
Winthrop Harbor, IL

Average sunshine days in September - Winthrop Harbor, IL
  • Average sunshine days in September: 13.9 days

The month with the most sunshine days is November (16.5 days).
The month with the least sunshine days is July (10.8 days).

Average UV index in September
Winthrop Harbor, IL

Average UV index in September - Winthrop Harbor, IL
  • Average UV index in September: 4

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

Average cloud cover in September
Winthrop Harbor, IL

Average cloud cover in September - Winthrop Harbor, IL
  • Average cloud cover in September: 29

The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 27).

Average visibility in September
Winthrop Harbor, IL

Average visibility in September - Winthrop Harbor, 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).

Winthrop Harbor, Illinois, USA

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