September weather forecast
Griggsville, IL

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Weather in September

September, the first month of the autumn in Griggsville, is also a moderately hot month, with temperature in the range of an average low of 58.6°F (14.8°C) and an average high of 78.3°F (25.7°C).

Temperature

Griggsville's weather in September indicates an average high-temperature of a still moderately hot 78.3°F (25.7°C), nearly consistent with the 83.5°F (28.6°C) of August. During September, the temperature is averaged to a low of 58.6°F (14.8°C) at night.

Humidity

In September, the average relative humidity is 74%.

Rainfall

In Griggsville, in September, during 10.5 rainfall days, 1.65" (42mm) of precipitation is typically accumulated. Throughout the year, there are 128.8 rainfall days, and 18.35" (466mm) of precipitation is accumulated.

Snowfall

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

Daylight

The average length of the day in September is 12h and 26min.
On the first day of the month, sunrise is at 6:31 am and sunset at 7:33 pm. On the last day of September, sunrise is at 6:58 am and sunset at 6:46 pm CDT.

Sunshine

In September, the average sunshine is 9.5h.

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 unprotected exposure to Sun's UV rays for the average person.
Note: In September, a daily maximum UV index of 5 leads to the following instructions:
Guard yourself - An obligation to protect skin and eyes from harm exists. Protect yourself from the midday Sun's peak UV radiation by minimizing exposure. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.
Updated: Jul 25, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

In September, the average high-temperature and low-temperature are 78.3°F (25.7°C) and 58.6°F (14.8°C) respectively. The average heat index (a.k.a. 'real feel', 'feels like'), which represents the influence of relative humidity on air temperature, in August is calculated to be 91.4°F (33°C).

What is the average humidity in September in Griggsville?

In September, the average relative humidity is 74%.

How many days does it rain in September in Griggsville?

In Griggsville, in September, it is raining for 10.5 days, with typically 1.65" (42mm) of accumulated precipitation.

When it does not snow?

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

What is the average length of the day in September?

In September, the average day length is 12h and 26min.

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 6:31 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 6:46 pm CDT.

How many hours of sunshine does Griggsville have in September?

In Griggsville, the average sunshine duration in September is 9.5h.

What is the UV index intensity in September?

In Griggsville, Illinois, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium health risk 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
Griggsville, IL

Average temperature in September - Griggsville, IL
  • Average high temperature in September: 78.3°F

The warmest month (with the highest average high temperature) is July (84.4°F).
The month with the lowest average high temperature is January (33.8°F).

  • Average low temperature in September: 58.6°F

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (21.6°F).

Average pressure in September
Griggsville, IL

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

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
Griggsville, IL

Average wind speed in September - Griggsville, IL
  • Average wind speed in September: 6.8mph

The windiest months (with the highest average wind speed) are January, February and April (9.8mph).
The calmest month (with the lowest average wind speed) is July (6mph).

Average humidity in September
Griggsville, IL

Average humidity in September - Griggsville, IL
  • Average humidity in September: 74%

The months with the highest relative humidity are June and July (81%).
The month with the lowest relative humidity is October (71%).

Average rainfall in September
Griggsville, IL

Average rainfall in September - Griggsville, IL
  • Average rainfall in September: 1.65"

The wettest month (with the highest rainfall) is May (2.44").
The driest month (with the least rainfall) is February (0.75").

Average rainfall days in September
Griggsville, IL

Average rainfall days in September - Griggsville, IL
  • Average rainfall days in September: 10.5 days

The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is January (4.5 days).

Average snowfall in September
Griggsville, IL

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

The month with the highest snowfall is January (2.05").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in September
Griggsville, IL

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

The month with the highest number of snowfall days is January (6.3 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
Griggsville, IL

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

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in September: 9h and 3min

The months with the most sunshine are June and July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).

Average sunshine days in September
Griggsville, IL

Average sunshine days in September - Griggsville, IL
  • Average sunshine days in September: 17.3 days

The month with the most sunshine days is December (20.7 days).
The month with the least sunshine days is June (12.3 days).

Average UV index in September
Griggsville, IL

Average UV index in September - Griggsville, IL
  • Average UV index in September: 5

The months with the highest UV index are 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
Griggsville, IL

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

The month with the most cloud cover is January (Cloud cover 52).
The months with the least cloud cover are June, July, August and September (Cloud cover 29).

Average visibility in September
Griggsville, IL

Average visibility in September - Griggsville, 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).

Griggsville, Illinois, USA

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