September weather forecast
Allendale, IL

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Weather in September

The first month of the autumn, September, is still a warm month in Allendale, Illinois, with an average temperature fluctuating between 60.6°F (15.9°C) and 78.8°F (26°C).

Temperature

With the arrival of September, Allendale's average high-temperature registers at a still moderately hot 78.8°F (26°C), indicating a subtle variation from the previous month. During September, the nighttime temperature averages of 60.6°F (15.9°C).

Humidity

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

Rainfall

The month with the least rainfall in Allendale is September, when the rain falls for 12.3 days and typically collects 1.85" (47mm) of precipitation.

Snowfall

May through October are months without snowfall.

Daylight

In September, the average length of the day in Allendale is 12h and 25min.
On the first day of September, sunrise is at 6:20 am and sunset at 7:20 pm. On the last day of the month, sunrise is at 6:46 am and sunset at 6:34 pm CDT.

Sunshine

In September, the average sunshine is 9.1h.

UV index

In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for the average person.
Note: The UV index of 5 in September translates into these instructions:
Preventative actions are necessary - Suggestions to safeguard against sun damage are in order. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.

Frequently asked questions

What are September temperatures?

During September, Allendale experiences an average high-temperature of 78.8°F (26°C) and a low-temperature of 60.6°F (15.9°C). The average heat index (a.k.a. 'real feel', 'felt air temperature'), which factors the actual air temperature with the relative humidity, in August is evaluated at 91.4°F (33°C).

What is the average humidity in September?

In September, the average relative humidity is 73%.

What is the driest month?

September is the month with the least rainfall. Rain falls for 12.3 days and accumulates 1.85" (47mm) of precipitation.

How much does it rain in September?

In Allendale, in September, during 12.3 rainfall days, 1.85" (47mm) of precipitation is typically accumulated.

When it does not snow?

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

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

In September, the average day length is 12h and 25min.

When is the sunrise / sunset in September in Allendale?

On the first day of September, sunrise is at 6:20 am and sunset at 7:20 pm. On the last day of the month, sunrise is at 6:46 am and sunset at 6:34 pm CDT.

How many hours of sunshine does Allendale have in September?

In Allendale, the average sunshine duration in September is 9.1h.

What is the UV index intensity in September?

The average daily maximum UV index in September is 5. 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
Allendale, IL

Average temperature in September - Allendale, IL
  • Average high temperature in September: 78.8°F

The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (37.9°F).

  • Average low temperature in September: 60.6°F

The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (24.8°F).

Average pressure in September
Allendale, IL

Average pressure in September - Allendale, 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
Allendale, IL

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

The windiest month (with the highest average wind speed) is February (10.1mph).
The calmest month (with the lowest average wind speed) is July (5.9mph).

Average humidity in September
Allendale, IL

Average humidity in September - Allendale, IL
  • Average humidity in September: 73%

The months with the highest relative humidity are May and July (80%).
The month with the lowest relative humidity is October (70%).

Average rainfall in September
Allendale, IL

Average rainfall in September - Allendale, IL
  • Average rainfall in September: 1.85"

The wettest month (with the highest rainfall) is April (4.72").
The driest month (with the least rainfall) is September (1.85").

Average rainfall days in September
Allendale, IL

Average rainfall days in September - Allendale, IL
  • Average rainfall days in September: 12.3 days

The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is January (9.4 days).

Average snowfall in September
Allendale, IL

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

The month with the highest snowfall is January (1.46").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in September
Allendale, IL

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

The month with the highest number of snowfall days is January (6.8 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
Allendale, IL

Average daylight in September / Average sunshine in September - Allendale, 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 1min

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 18min).

Average sunshine days in September
Allendale, IL

Average sunshine days in September - Allendale, IL
  • Average sunshine days in September: 15.9 days

The month with the most sunshine days is October (18.5 days).
The month with the least sunshine days is May (10.3 days).

Average UV index in September
Allendale, IL

Average UV index in September - Allendale, 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
Allendale, IL

Average cloud cover in September - Allendale, IL
  • Average cloud cover in September: 29

The month with the most cloud cover is January (Cloud cover 53).
The months with the least cloud cover are June and August (Cloud cover 28).

Average visibility in September
Allendale, IL

Average visibility in September - Allendale, 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).

Allendale, Illinois, USA

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