September weather forecast
Harvey, IL

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Weather in September

The first month of the autumn, September, is still a warm month in Harvey, Illinois, with an average temperature varying between 58.3°F (14.6°C) and 73.9°F (23.3°C).

Temperature

Harvey's September weather shows a modest shift in high-temperatures, falling from August's 80.1°F (26.7°C) to a still warm 73.9°F (23.3°C). Harvey temperatures generally rest at a low of 58.3°F (14.6°C) during the September nights.

Humidity

The average relative humidity in September is 76%.

Rainfall

In Harvey, during September, the rain falls for 13.4 days and regularly aggregates up to 2.48" (63mm) of precipitation. Throughout the year, there are 155.6 rainfall days, and 31.3" (795mm) of precipitation is accumulated.

Snowfall

May through September are months without snowfall.

Daylight

The average length of the day in September is 12h and 28min.
On the first day of the month, sunrise is at 6:17 am and sunset at 7:23 pm. On the last day of September, sunrise is at 6:47 am and sunset at 6:33 pm CDT.

Sunshine

In Harvey, the average sunshine in September is 8.8h.

UV index

In Harvey, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for average individuals.
Note: A maximum high UV index of 4 in September translates into the following recommendations:
Be mindful. Individuals with a lighter skin tone may suffer burns in less than 30 minutes. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. To cut down UV radiation exposure by about half, sport a wide-brim hat.

Frequently asked questions

What is the average September temperature?

In Harvey, 73.9°F (23.3°C) is the average high-temperature and 58.3°F (14.6°C) is the average low-temperature during September. In July, the average heat index (a.k.a. 'feels like', 'real feel'), which combines air temperature and relative humidity, is computed to be 87.8°F (31°C).

What is the average humidity in September?

In September, the average relative humidity is 76%.

How many days does it rain in September?

In September, in Harvey, the rain falls for 13.4 days. Throughout September, 2.48" (63mm) of precipitation is accumulated.

When it does not snow in Harvey?

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

Does it snow in Harvey in September?

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

How many hours of daylight does Harvey have in September?

In Harvey, the average day length in September is 12h and 28min.

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 6:17 am and sunset at 7:23 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:33 pm CDT.

How long on average sun shines in September?

In Harvey, Illinois, the average sunshine duration in September is 8.8h.

What is the UV index intensity in September?

In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a medium hazard to health 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
Harvey, IL

Average temperature in September - Harvey, IL
  • Average high temperature in September: 73.9°F

The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (29.7°F).

  • Average low temperature in September: 58.3°F

The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).

Average pressure in September
Harvey, IL

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

The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in September
Harvey, IL

Average wind speed in September - Harvey, IL
  • Average wind speed in September: 7.3mph

The windiest month (with the highest average wind speed) is January (10.2mph).
The calmest month (with the lowest average wind speed) is August (6.3mph).

Average humidity in September
Harvey, IL

Average humidity in September - Harvey, IL
  • Average humidity in September: 76%

The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (73%).

Average rainfall in September
Harvey, IL

Average rainfall in September - Harvey, IL
  • Average rainfall in September: 2.48"

The wettest month (with the highest rainfall) is May (4.17").
The driest month (with the least rainfall) is December (1.54").

Average rainfall days in September
Harvey, IL

Average rainfall days in September - Harvey, IL
  • Average rainfall days in September: 13.4 days

The month with the highest number of rainy days is July (17.6 days).
The month with the least rainy days is February (6.1 days).

Average snowfall in September
Harvey, IL

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

The month with the highest snowfall is January (4.53").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Harvey, IL

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

The month with the highest number of snowfall days is January (12.6 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

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

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

  • Average sunshine in September: 8h and 5min

The month with the most sunshine is August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).

Average sunshine days in September
Harvey, IL

Average sunshine days in September - Harvey, IL
  • Average sunshine days in September: 14 days

The month with the most sunshine days is November (16.4 days).
The month with the least sunshine days is April (10.2 days).

Average UV index in September
Harvey, IL

Average UV index in September - Harvey, IL
  • Average UV index in September: 4

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

Average cloud cover in September
Harvey, IL

Average cloud cover in September - Harvey, IL
  • Average cloud cover in September: 32

The month with the most cloud cover is January (Cloud cover 62).
The month with the least cloud cover is August (Cloud cover 30).

Average visibility in September
Harvey, IL

Average visibility in September - Harvey, IL
  • Average visibility in September: 6mi

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

Harvey, Illinois, USA

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