September weather forecastRound Lake, IL
September
Weather in September
The first month of the autumn, September, is also an agreeable month in Round Lake, Illinois, with an average temperature ranging between min 57°F (13.9°C) and max 72.3°F (22.4°C).Temperature
September is characterized by a mild reduction in the average high-temperature, from a moderately hot 78.6°F (25.9°C) in August to a pleasant 72.3°F (22.4°C). Round Lake experiences a nighttime temperature average of 57°F (13.9°C) during September.Humidity
In Round Lake, the average relative humidity in September is 77%.Rainfall
In Round Lake, in September, it is raining for 11.9 days, with typically 1.57" (40mm) of accumulated precipitation. Throughout the year, there are 142.3 rainfall days, and 21.97" (558mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall.Daylight
The average length of the day in September is 12h and 28min.On the first day of September, sunrise is at 6:18 am and sunset at 7:25 pm. On the last day of the month, sunrise is at 6:49 am and sunset at 6:35 pm CDT.
Sunshine
In Round Lake, the average sunshine in September is 8.9h.UV index
In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for average individuals.Note: In September, the maximum UV index of 4 suggests these recommendations:
Put precautions into practice - Ensuring skin and eye safety is a necessity. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Round Lake, IL
- Average high temperature in September: 72.3°F
The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is January (27.5°F).
- Average low temperature in September: 57°F
The month with the highest average low temperature is July (64.4°F).
The coldest month (with the lowest average low temperature) is January (16.5°F).
Average pressure in September
Round Lake, IL
- Average pressure in September: 30.03"Hg
The months with the highest atmospheric pressure are January and February (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Round Lake, IL
- Average wind speed in September: 7.5mph
The windiest month (with the highest average wind speed) is January (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.4mph).
Average humidity in September
Round Lake, IL
- Average humidity in September: 77%
The months with the highest relative humidity are January and February (83%).
The month with the lowest relative humidity is October (74%).
Average rainfall in September
Round Lake, IL
- Average rainfall in September: 1.57"
The wettest month (with the highest rainfall) is April (2.72").
The driest month (with the least rainfall) is December (0.98").
Average rainfall days in September
Round Lake, IL
- Average rainfall days in September: 11.9 days
The month with the highest number of rainy days is July (17.5 days).
The month with the least rainy days is February (5 days).
Average snowfall in September
Round Lake, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.58").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Round Lake, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (13.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Round Lake, IL
- Average daylight in September: 12h and 30min
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 6min).
- Average sunshine in September: 8h and 54min
The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Round Lake, IL
- Average sunshine days in September: 15.1 days
The month with the most sunshine days is November (17.1 days).
The month with the least sunshine days is May (10.8 days).
Average UV index in September
Round Lake, IL
- Average UV index in September: 4
The months with the highest UV index are 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
Round Lake, IL
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 61).
The months with the least cloud cover are July, August and September (Cloud cover 30).
Average visibility in September
Round Lake, IL
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
