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 commencement of September introduces an average high-temperature of a still warm 75.6°F (24.2°C), closely mirroring the preceding month. Merna's nighttime temperature in September falls to an average of 57.4°F (14.1°C).Humidity
The average relative humidity in September is 77%.Rainfall
In Merna, in September, during 13.2 rainfall days, 2.2" (56mm) of precipitation is typically accumulated. Throughout the year, in Merna, there are 163.1 rainfall days, and 33.62" (854mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
In September, the average length of the day in Merna is 12h and 27min.On the first day of September in Merna, sunrise is at 6:23 am and sunset at 7:26 pm. On the last day of the month, sunrise is at 6:51 am and sunset at 6:38 pm CDT.
Sunshine
The average sunshine in September in Merna is 8.8h.UV index
In September, the average daily maximum UV index in Merna is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for the ordinary person.Note: The maximum UV index, 5 during September, leads to the following recommendations:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures in Merna?
What is the average humidity in September in Merna?
How many days does it rain in September in Merna?
When it does not snow in Merna?
Does it snow in Merna in September?
How many hours of daylight does Merna have in September?
When is the sunrise / sunset in September in Merna?
How many hours of sunshine does Merna have in September?
How high is the UV index in September in Merna?
Average temperature in September
Merna, IL
- Average high temperature in September: 75.6°F
The warmest month (with the highest average high temperature) is July (80.8°F).
The month with the lowest average high temperature is January (30.7°F).
- Average low temperature in September: 57.4°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in September
Merna, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Merna, IL
- Average wind speed in September: 7.7mph
The windiest month (with the highest average wind speed) is January (11.1mph).
The calmest month (with the lowest average wind speed) is August (6.6mph).
Average humidity in September
Merna, IL
- Average humidity in September: 77%
The month with the highest relative humidity is July (86%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Merna, IL
- Average rainfall in September: 2.2"
The wettest month (with the highest rainfall) is May (4.57").
The driest month (with the least rainfall) is December (1.93").
Average rainfall days in September
Merna, IL
- Average rainfall days in September: 13.2 days
The month with the highest number of rainy days is May (20.1 days).
The month with the least rainy days is February (6.9 days).
Average snowfall in September
Merna, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (5.04").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Merna, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (12.8 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
Merna, IL
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 8h and 5min
The month with the most sunshine is June (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Merna, IL
- Average sunshine days in September: 14.5 days
The month with the most sunshine days is November (17.4 days).
The month with the least sunshine days is May (8.4 days).
Average UV index in September
Merna, IL
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in September
Merna, IL
- Average cloud cover in September: 33
The month with the most cloud cover is January (Cloud cover 60).
The months with the least cloud cover are August and September (Cloud cover 33).
Average visibility in September
Merna, IL
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).
Merna, Illinois, USA
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