September weather forecast
Hartford, IL

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Weather in September

The first month of the autumn, September, is still a warm month in Hartford, Illinois, with temperature in the range of an average high of 78.6°F (25.9°C) and an average low of 59.4°F (15.2°C).

Temperature

In Hartford, the average high-temperature in September gently drops from 84°F (28.9°C) in August to a still moderately hot 78.6°F (25.9°C). During the month of September, Hartford anticipates a mean low-temperature of 59.4°F (15.2°C).

Humidity

In Hartford, Illinois, the average relative humidity in September is 75%.

Rainfall

In September, the rain falls for 11.8 days. Throughout September, 1.69" (43mm) of precipitation is accumulated. In Hartford, during the entire year, the rain falls for 138 days and collects up to 23.9" (607mm) of precipitation.

Snowfall

In Hartford, snow does not fall in May through October.

Daylight

In Hartford, the average length of the day in September is 12h and 26min.
On the first day of September, sunrise is at 6:30 am and sunset at 7:30 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 6:44 pm CDT.

Sunshine

The average sunshine in September is 9.3h.

UV index

In September, the average daily maximum UV index is 5. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: The maximum daily UV index of 5 in September converts into the following recommendations:
Preventative actions are necessary - Recommendations to ward off sunburn are given. Around midday, solar radiation is most harmful; hence, exposure should be limited. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage.
Updated: Jun 24, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September?

In September, the average high-temperature and low-temperature are 78.6°F (25.9°C) and 59.4°F (15.2°C) respectively. The average heat index (a.k.a. 'apparent temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, in August is appraised at 93.2°F (34°C).

What is the average humidity in September?

In Hartford, the average relative humidity in September is 75%.

How many days does it rain in September?

In Hartford, in September, during 11.8 rainfall days, 1.69" (43mm) of precipitation is typically accumulated.

When it does not snow?

May through October are months without snowfall.

How many hours of daylight does Hartford have in September?

The average day length in September is 12h and 26min.

What time are sunrise and sunset in September?

On the first day of September, sunrise is at 6:30 am and sunset at 7:30 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 6:44 pm CDT.

How long on average sun shines in September?

In September, the average sunshine duration in Hartford is 9.3h.

How high is the UV index in September?

In Hartford, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a medium health risk 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
Hartford, IL

Average temperature in September - Hartford, IL
  • Average high temperature in September: 78.6°F

The warmest month (with the highest average high temperature) is July (85.3°F).
The month with the lowest average high temperature is January (36.1°F).

  • Average low temperature in September: 59.4°F

The month with the highest average low temperature is July (67.6°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).

Average pressure in September
Hartford, IL

Average pressure in September - Hartford, IL
  • Average pressure in September: 30.02"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in September
Hartford, IL

Average wind speed in September - Hartford, IL
  • Average wind speed in September: 6.3mph

The windiest months (with the highest average wind speed) are January and February (9.6mph).
The calmest month (with the lowest average wind speed) is July (5.7mph).

Average humidity in September
Hartford, IL

Average humidity in September - Hartford, IL
  • Average humidity in September: 75%

The month with the highest relative humidity is July (80%).
The month with the lowest relative humidity is October (71%).

Average rainfall in September
Hartford, IL

Average rainfall in September - Hartford, IL
  • Average rainfall in September: 1.69"

The wettest month (with the highest rainfall) is May (3.07").
The driest month (with the least rainfall) is February (1.14").

Average rainfall days in September
Hartford, IL

Average rainfall days in September - Hartford, IL
  • Average rainfall days in September: 11.8 days

The month with the highest number of rainy days is May (16.6 days).
The month with the least rainy days is January (5.6 days).

Average snowfall in September
Hartford, IL

Average snowfall in September - Hartford, IL
  • Average snowfall in September: 0"

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

Average snowfall days in September
Hartford, IL

Average snowfall days in September - Hartford, IL
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (6 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Hartford, IL

Average daylight in September / Average sunshine in September - Hartford, 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 30min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is June (Average sunshine: 10h and 24min).
The months with the least sunshine are January and February (Average sunshine: 4h and 30min).

Average sunshine days in September
Hartford, IL

Average sunshine days in September - Hartford, IL
  • Average sunshine days in September: 15.7 days

The month with the most sunshine days is December (20.4 days).
The month with the least sunshine days is July (12.3 days).

Average UV index in September
Hartford, IL

Average UV index in September - Hartford, 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
Hartford, IL

Average cloud cover in September - Hartford, IL
  • Average cloud cover in September: 30

The month with the most cloud cover is January (Cloud cover 51).
The months with the least cloud cover are June, July and August (Cloud cover 29).

Average visibility in September
Hartford, IL

Average visibility in September - Hartford, 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).

Hartford, Illinois, USA

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