September weather forecast
New Haven, IL

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Weather in September

The first month of the autumn, September, is also a moderately hot month in New Haven, Illinois, with an average temperature varying between 60.8°F (16°C) and 79.5°F (26.4°C).

Temperature

The transition into September shows a subtle variation to a still warm 79.5°F (26.4°C) from August's 84.4°F (29.1°C) in the average high-temperature. New Haven's nighttime temperature in September drops to an average of 60.8°F (16°C).

Humidity

In New Haven, the average relative humidity in September is 73%.

Rainfall

The month with the least rainfall in New Haven is September, when the rain falls for 7.3 days and typically collects 0.28" (7mm) of precipitation.

Snowfall

In New Haven, snow does not fall in April through October.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of the month, sunrise is at 6:23 am and sunset at 7:21 pm. On the last day of September, sunrise is at 6:47 am and sunset at 6:36 pm CDT.

Sunshine

In New Haven, the average sunshine in September is 9.3h.

UV index

In New Haven, Illinois, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for average individuals.
Note: The daily high UV index of 5 in September translates into this advice:
Take necessary precautions - Suggestions to elude sunburn are provided. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Stay sun-safe with clothing that is both closely woven and worn loosely.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in New Haven in September?

The high-temperature in New Haven during September is 79.5°F (26.4°C) and the low-temperature is 60.8°F (16°C). In August, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which calculates the temperature value influenced by the moisture in the air, is evaluated at 95°F (35°C).

What is the average humidity in September in New Haven?

In September, the average relative humidity in New Haven, Illinois, is 73%.

What is the driest month in New Haven?

September is the month with the least rainfall in New Haven. Rain falls for 7.3 days and accumulates 0.28" (7mm) of precipitation.

How many days does it rain in September in New Haven?

In September, in New Haven, Illinois, the rain falls for 7.3 days. Throughout September, 0.28" (7mm) of precipitation is accumulated.

When it does not snow in New Haven?

April through October are months without snowfall in New Haven, Illinois.

How many hours of daylight does New Haven have in September?

The average day length in September in New Haven is 12h and 25min.

When is the sunrise / sunset in September in New Haven?

In September, on the first day of the month, sunrise is at 6:23 am and sunset at 7:21 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:36 pm CDT.

How long on average sun shines in September in New Haven?

In September, the average sunshine duration is 9.3h.

What is the UV index reading in September in New Haven?

In New Haven, Illinois, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate vulnerability from unprotected exposure to UV radiation.
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
New Haven, IL

Average temperature in September - New Haven, IL
  • Average high temperature in September: 79.5°F

The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is January (38.3°F).

  • Average low temperature in September: 60.8°F

The month with the highest average low temperature is July (68.2°F).
The coldest month (with the lowest average low temperature) is January (26.1°F).

Average pressure in September
New Haven, IL

Average pressure in September - New Haven, IL
  • Average pressure in September: 30.03"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed in September
New Haven, IL

Average wind speed in September - New Haven, IL
  • Average wind speed in September: 6.7mph

The windiest month (with the highest average wind speed) is February (10.1mph).
The calmest months (with the lowest average wind speed) are July and August (6mph).

Average humidity in September
New Haven, IL

Average humidity in September - New Haven, IL
  • Average humidity in September: 73%

The months with the highest relative humidity are May and July (79%).
The month with the lowest relative humidity is October (69%).

Average rainfall in September
New Haven, IL

Average rainfall in September - New Haven, IL
  • Average rainfall in September: 0.28"

The wettest month (with the highest rainfall) is April (1.06").
The driest month (with the least rainfall) is September (0.28").

Average rainfall days in September
New Haven, IL

Average rainfall days in September - New Haven, IL
  • Average rainfall days in September: 7.3 days

The month with the highest number of rainy days is May (11.9 days).
The month with the least rainy days is January (5 days).

Average snowfall in September
New Haven, IL

Average snowfall in September - New Haven, IL
  • Average snowfall in September: 0"

The months with the highest snowfall are January and February (0.28").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in September
New Haven, IL

Average snowfall days in September - New Haven, IL
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (3.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average daylight in September /
Average sunshine in September
New Haven, IL

Average daylight in September / Average sunshine in September - New Haven, IL
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is June (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).

Average sunshine days in September
New Haven, IL

Average sunshine days in September - New Haven, IL
  • Average sunshine days in September: 20.4 days

The month with the most sunshine days is October (23.4 days).
The month with the least sunshine days is May (15.8 days).

Average UV index in September
New Haven, IL

Average UV index in September - New Haven, IL
  • Average UV index in September: 5

The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in September
New Haven, IL

Average cloud cover in September - New Haven, IL
  • Average cloud cover in September: 28

The months with the most cloud cover are January and February (Cloud cover 51).
The months with the least cloud cover are June and August (Cloud cover 27).

Average visibility in September
New Haven, IL

Average visibility in September - New Haven, 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).

New Haven, Illinois, USA

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