Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
September witnesses a gentle descent in average high-temperature, descending from August's moderately hot 84.9°F (29.4°C) to a still warm 79.2°F (26.2°C). Grafton experiences a consistent average temperature of 59.7°F (15.4°C) throughout the nights in September.Humidity
In Grafton, Illinois, the average relative humidity in September is 74%.Rainfall
In September, the rain falls for 11.6 days. Throughout September, 2.01" (51mm) of precipitation is accumulated. Throughout the year, there are 138.8 rainfall days, and 27.6" (701mm) of precipitation is accumulated.Snowfall
April through October are months without snowfall in Grafton.Daylight
The average length of the day in September is 12h and 26min.On the first day of September in Grafton, sunrise is at 6:31 am and sunset at 7:31 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:45 pm CDT.
Sunshine
The average sunshine in September is 9.4h.UV index
In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for the ordinary person.Note: A daily maximum UV index of 5 in September translates into the following instructions:
Exercise care. People with light skin might get burns in fewer than 30 minutes. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Grafton in September?
What is the average humidity in September in Grafton?
How many days does it rain in September in Grafton?
When it does not snow in Grafton?
What is the average length of the day in September in Grafton?
When are sunrise and sunset in September in Grafton?
How many hours of sunshine does Grafton have in September?
How high is the UV index in September in Grafton?
Average temperature in September
Grafton, IL
- Average high temperature in September: 79.2°F
The warmest month (with the highest average high temperature) is July (86.4°F).
The month with the lowest average high temperature is January (36.1°F).
- Average low temperature in September: 59.7°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 (23.4°F).
Average pressure in September
Grafton, 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
Grafton, IL
- Average wind speed in September: 6.2mph
The windiest month (with the highest average wind speed) is January (9.4mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).
Average humidity in September
Grafton, IL
- Average humidity in September: 74%
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Grafton, IL
- Average rainfall in September: 2.01"
The wettest month (with the highest rainfall) is May (3.35").
The driest month (with the least rainfall) is February (1.3").
Average rainfall days in September
Grafton, IL
- Average rainfall days in September: 11.6 days
The month with the highest number of rainy days is July (16.3 days).
The month with the least rainy days is January (6.3 days).
Average snowfall in September
Grafton, IL
- Average snowfall in September: 0"
The months with the highest snowfall are January and February (1.54").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Grafton, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (5.7 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
Grafton, 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 30min).
- Average sunshine in September: 9h and 2min
The months with the most sunshine are June and July (Average sunshine: 10h and 24min).
The months with the least sunshine are January and February (Average sunshine: 4h and 36min).
Average sunshine days in September
Grafton, IL
- Average sunshine days in September: 16.4 days
The month with the most sunshine days is December (19.8 days).
The month with the least sunshine days is June (11.2 days).
Average UV index in September
Grafton, 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
Grafton, IL
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in September
Grafton, 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).
Grafton, Illinois, USA
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