September weather forecast
Watertown, WI

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Weather in September

September ushers in the fall season in Watertown, Wisconsin. It's a transition period that blends the lingering warmth of summer with the fresh, crisp air of the incoming autumn. Noticeably cooler weather steps in, with temperatures situated between 52°F (11.1°C) and 70.9°F (21.6°C). September holds a balance between rainy days and sunshine, providing the city with a pleasant ambient environment. The fall foliage begins to show, adding hues of orange, yellow, and red to the city's landscape.

Temperature

September sees a slight reduction in average high-temperature, with a shift from a moderately hot 77.5°F (25.3°C) in August to an agreeable 70.9°F (21.6°C). September nights are marked by an average low-temperature of 52°F (11.1°C).

Humidity

In September, the average relative humidity in Watertown is 81%.

Rainfall

In September, in Watertown, the rain falls for 9.8 days. Throughout September, 0.91" (23mm) of precipitation is accumulated. Throughout the year, in Watertown, there are 113.9 rainfall days, and 11.57" (294mm) of precipitation is accumulated.

Snowfall

June through September are months without snowfall in Watertown.

Daylight

In Watertown, Wisconsin, the average length of the day in September is 12h and 29min.
On the first day of September in Watertown, sunrise is at 6:20 am and sunset at 7:29 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:37 pm CDT.

Sunshine

In September, the average sunshine in Watertown is 8.6h.

UV index

In Watertown, Wisconsin, the average daily maximum UV index in September is 3. A UV Index estimate of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: A maximum daily UV index of 3 during September morphs into the following directions:
Ensure safety - Recommendations to avert sunburn are presented. Protect yourself from the midday Sun's peak UV radiation by minimizing exposure. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes.
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Frequently asked questions

What are September temperatures in Watertown?

September temperatures in Watertown, Wisconsin, vary between a high-temperature of 70.9°F (21.6°C) and a low-temperature of 52°F (11.1°C).

What is the average humidity in September in Watertown?

The average relative humidity in September in Watertown is 81%.

How much does it rain in Watertown in September?

In Watertown, in September, during 9.8 rainfall days, 0.91" (23mm) of precipitation is typically accumulated.

When it does not snow in Watertown?

June through September are months without snowfall in Watertown, Wisconsin.

Does it snow in Watertown in September?

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

What is the average length of the day in September in Watertown?

In Watertown, Wisconsin, the average day length in September is 12h and 29min.

When is the sunrise / sunset in September in Watertown?

In September, on the first day of the month, sunrise is at 6:20 am and sunset at 7:29 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:37 pm CDT.

How many hours of sunshine does Watertown have in September?

In September, the average sunshine duration in Watertown, Wisconsin, is 8.6h.

How high is the UV index in September in Watertown?

In September, the average daily maximum UV index in Watertown, Wisconsin, is 3. A UV Index value of 3 to 5 symbolizes a moderate health threat from unsafe 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
Watertown, WI

Average temperature in September - Watertown, WI
  • Average high temperature in September: 70.9°F

The warmest month (with the highest average high temperature) is July (78.6°F).
The month with the lowest average high temperature is January (23.7°F).

  • Average low temperature in September: 52°F

The month with the highest average low temperature is July (61.3°F).
The coldest month (with the lowest average low temperature) is January (11.7°F).

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Average pressure in September
Watertown, WI

Average pressure in September - Watertown, WI
  • Average pressure in September: 30.03"Hg

The months with the highest atmospheric pressure are January and February (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in September
Watertown, WI

Average wind speed in September - Watertown, WI
  • Average wind speed in September: 7.4mph

The windiest month (with the highest average wind speed) is April (10mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).

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Average humidity in September
Watertown, WI

Average humidity in September - Watertown, WI
  • Average humidity in September: 81%

The month with the highest relative humidity is January (89%).
The month with the lowest relative humidity is April (76%).

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Average rainfall in September
Watertown, WI

Average rainfall in September - Watertown, WI
  • Average rainfall in September: 0.91"

The wettest month (with the highest rainfall) is July (1.54").
The driest months (with the least rainfall) are February and December (0.47").

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Average rainfall days in September
Watertown, WI

Average rainfall days in September - Watertown, WI
  • Average rainfall days in September: 9.8 days

The month with the highest number of rainy days is May (14.4 days).
The month with the least rainy days is February (3 days).

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Average snowfall in September
Watertown, WI

Average snowfall in September - Watertown, WI
  • Average snowfall in September: 0"

The month with the highest snowfall is January (1.61").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in September
Watertown, WI

Average snowfall days in September - Watertown, WI
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (12.1 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in September / Average sunshine in September - Watertown, WI
  • 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 0min).

  • Average sunshine in September: 8h and 4min

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 24min).

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Average sunshine days in September
Watertown, WI

Average sunshine days in September - Watertown, WI
  • Average sunshine days in September: 16.5 days

The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is July (12.4 days).

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Average UV index in September
Watertown, WI

Average UV index in September - Watertown, WI
  • Average UV index in September: 3

The months with the highest UV index are May, June, July and August (UV index 5).
The months with the lowest UV index are January, November and December (UV index 1).

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Average cloud cover in September
Watertown, WI

Average cloud cover in September - Watertown, WI
  • Average cloud cover in September: 34

The month with the most cloud cover is January (Cloud cover 65).
The months with the least cloud cover are July, August and September (Cloud cover 34).

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Average visibility in September
Watertown, WI

Average visibility in September - Watertown, WI
  • Average visibility in September: 5mi

The months with the highest visibility are March, April, May, June, October, November and December (6mi).
The months with the lowest visibility are January, February, July, August and September (5mi).

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Watertown, Wisconsin, USA

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