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 shift into September records an average high-temperature of a still moderately hot 77.2°F (25.1°C), subtly varied from August's 81.1°F (27.3°C). In Lerna, an average nighttime temperature of 58.5°F (14.7°C) is expected during September.Humidity
In September, the average relative humidity is 76%.Rainfall
In September, in Lerna, the rain falls for 12.1 days. Throughout September, 1.38" (35mm) of precipitation is accumulated. In Lerna, during the entire year, the rain falls for 148 days and collects up to 25.63" (651mm) of precipitation.Snowfall
May through September are months without snowfall.Daylight
In September, the average length of the day is 12h and 26min.On the first day of the month, sunrise is at 6:22 am and sunset at 7:23 pm. On the last day of September, sunrise is at 6:49 am and sunset at 6:36 pm CDT.
Sunshine
In September, the average sunshine in Lerna is 8.9h.UV index
In September, the average daily maximum UV index in Lerna is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for average individuals.Note: The UV index of 5 during September translates into the following guidance:
Be vigilant - A duty to shield skin and eyes from injury exists. The midday Sun can be dangerous due to its intense radiation; always find shade and reduce exposure. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Frequently asked questions
What is the temperature in September in Lerna?
What is the average humidity in September in Lerna?
How many days does it rain in September in Lerna?
When it does not snow in Lerna?
Does it snow in Lerna in September?
How many hours of daylight does Lerna have in September?
When are sunrise and sunset in September in Lerna?
How many hours of sunshine does Lerna have in September?
What is the UV index reading in September in Lerna?
Average temperature in September
Lerna, IL
- Average high temperature in September: 77.2°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (34°F).
- Average low temperature in September: 58.5°F
The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (21.9°F).
Average pressure in September
Lerna, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Lerna, IL
- Average wind speed in September: 7.1mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest month (with the lowest average wind speed) is July (6.2mph).
Average humidity in September
Lerna, IL
- Average humidity in September: 76%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (70%).
Average rainfall in September
Lerna, IL
- Average rainfall in September: 1.38"
The wettest month (with the highest rainfall) is April (3.31").
The driest month (with the least rainfall) is February (1.3").
Average rainfall days in September
Lerna, IL
- Average rainfall days in September: 12.1 days
The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is February (7.8 days).
Average snowfall in September
Lerna, IL
- Average snowfall in September: 0"
The month with the highest snowfall is December (2.13").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Lerna, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.1 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
Lerna, 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: 8h and 5min
The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in September
Lerna, IL
- Average sunshine days in September: 15.7 days
The month with the most sunshine days is October (18.3 days).
The month with the least sunshine days is July (10.6 days).
Average UV index in September
Lerna, IL
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Lerna, IL
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is June (Cloud cover 31).
Average visibility in September
Lerna, IL
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
Lerna, Illinois, USA
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