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
The advent of September brings a slight shift in average high-temperature, moving from a hot 86.5°F (30.3°C) in August to a moderately hot 81°F (27.2°C). September nights are marked by an average low-temperature of 60.6°F (15.9°C).Heat index
During September, the heat index is appraised at 84.2°F (29°C). With sustained exposure and activity, exhaustion becomes probable, resulting in heat cramps.Note that heat index values are valued for light wind and location in the shade. Direct sunlight exposure may result in a rise of the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', shows a temperature sensation when both heat and moisture conditions are combined. Elements such as metabolic variations, pregnancy, and physical exertion can shape one's weather perception. Awareness is key; direct sunlight can enhance the weather's impact, possibly boosting the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are primarily vital for children. Youths are typically more endangered than adults since they usually sweat less. Their larger skin surface concerning their smaller bodies and higher heat production due to activity further adds to their vulnerability.
Humidity
In September, the average relative humidity is 73%.Rainfall
September is the month with the least rainfall. Rain falls for 10.8 days and accumulates 1.3" (33mm) of precipitation.Snowfall
May through September are months without snowfall.Daylight
In September, the average length of the day is 12h and 25min.On the first day of the month, sunrise is at 6:28 am and sunset at 7:25 pm. On the last day of September, sunrise is at 6:52 am and sunset at 6:41 pm CDT.
Sunshine
In September, the average sunshine is 9.5h.UV index
In Alto Pass, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for the ordinary person.Note: A maximum daily UV index of 5 during September morphs into the following directions:
Take precautions - Protection against skin and eye damage is obliged. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures in Alto Pass?
What is the average humidity in September?
What is the driest month?
How much does it rain in September?
When it does not snow?
Does it snow in September?
How many hours of daylight does Alto Pass have in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Alto Pass have in September?
What is the UV index reading in September?
Average temperature in September
Alto Pass, IL
- Average high temperature in September: 81°F
The warmest month (with the highest average high temperature) is July (88.3°F).
The month with the lowest average high temperature is January (39.7°F).
- Average low temperature in September: 60.6°F
The month with the highest average low temperature is July (69.1°F).
The coldest month (with the lowest average low temperature) is January (26.8°F).
Average pressure in September
Alto Pass, 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 (29.94"Hg).
Average wind speed in September
Alto Pass, IL
- Average wind speed in September: 6.2mph
The windiest month (with the highest average wind speed) is January (9mph).
The calmest month (with the lowest average wind speed) is August (5.6mph).
Average humidity in September
Alto Pass, IL
- Average humidity in September: 73%
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Alto Pass, IL
- Average rainfall in September: 1.3"
The wettest month (with the highest rainfall) is April (3.31").
The driest month (with the least rainfall) is September (1.3").
Average rainfall days in September
Alto Pass, IL
- Average rainfall days in September: 10.8 days
The month with the highest number of rainy days is July (15.9 days).
The month with the least rainy days is January (8.4 days).
Average snowfall in September
Alto Pass, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.89").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Alto Pass, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.6 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
Alto Pass, IL
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in September: 9h and 3min
The month with the most sunshine is 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
Alto Pass, IL
- Average sunshine days in September: 17.5 days
The month with the most sunshine days is October (21 days).
The month with the least sunshine days is July (12.8 days).
Average UV index in September
Alto Pass, 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 and December (UV index 2).
Average cloud cover in September
Alto Pass, IL
- Average cloud cover in September: 28
The month with the most cloud cover is February (Cloud cover 51).
The month with the least cloud cover is September (Cloud cover 28).
Average visibility in September
Alto Pass, 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).
Alto Pass, Illinois, USA
Weather forecast for your location
2. Allow the app to use your location