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
Westchester's weather subtly changes with the onset of September, barely falling from a warm 80.2°F (26.8°C) in August to a still moderately hot 73.4°F (23°C). The mean low-temperature during September nights is a moderate 58.6°F (14.8°C).Humidity
The average relative humidity in September in Westchester is 74%.Rainfall
In Westchester, in September, it is raining for 13.5 days, with typically 1.89" (48mm) of accumulated precipitation. In Westchester, during the entire year, the rain falls for 149.4 days and collects up to 25.08" (637mm) of precipitation.Snowfall
In Westchester, Illinois, snow does not fall in June through September.Daylight
In September, the average length of the day in Westchester is 12h and 28min.On the first day of September, sunrise is at 6:18 am and sunset at 7:24 pm. On the last day of the month, sunrise is at 6:48 am and sunset at 6:34 pm CDT.
Sunshine
In Westchester, Illinois, the average sunshine in September is 8.8h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.Note: The UV index of 4 in September translates into these instructions:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. Around midday, solar radiation is most harmful; hence, exposure should be limited. Enhance your sun protection with tightly woven, yet airy clothing.
Frequently asked questions
What is the usual temperature for Westchester in September?
What is the average humidity in September in Westchester?
How many days does it rain in September in Westchester?
When it does not snow in Westchester?
Does it snow in Westchester in September?
What is the average length of the day in September in Westchester?
When is the sunrise / sunset in September in Westchester?
How long on average sun shines in September in Westchester?
What is the UV index reading in September in Westchester?
Average temperature in September
Westchester, IL
- Average high temperature in September: 73.4°F
The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (28.8°F).
- Average low temperature in September: 58.6°F
The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (18°F).
Average pressure in September
Westchester, 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
Westchester, IL
- Average wind speed in September: 7.5mph
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
Westchester, IL
- Average humidity in September: 74%
The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Westchester, IL
- Average rainfall in September: 1.89"
The wettest month (with the highest rainfall) is May (3.11").
The driest month (with the least rainfall) is December (1.14").
Average rainfall days in September
Westchester, IL
- Average rainfall days in September: 13.5 days
The months with the highest number of rainy days are May and July (17.3 days).
The month with the least rainy days is February (5.1 days).
Average snowfall in September
Westchester, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (3.86").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Westchester, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (12.4 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Westchester, IL
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 8h and 5min
The months with the most sunshine are July and August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Westchester, IL
- Average sunshine days in September: 13 days
The month with the most sunshine days is November (16.8 days).
The month with the least sunshine days is July (9.5 days).
Average UV index in September
Westchester, IL
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Westchester, IL
- Average cloud cover in September: 31
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in September
Westchester, 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).
Westchester, Illinois, USA
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