September weather forecastCalmar, IA
September
Weather in September
The conditions in September in Calmar take a gradual turn from heated summer days to milder autumn temperatures. It retains the warmth of the summer, but the intense heat starts loosening its grip. The landscape undergoes a transformation as leaves start exhibiting hues from a vast palette of red, orange, yellow, brown. Rainfall is more sporadic but does not hinder outdoor activities and seasonal events that take place regularly during the month. It's a picturesque time of the year, with stunning fall foliage coupled with perfectly comfortable weather for exploration.Temperature
The arrival of September in Calmar signals a subtle shift in temperature, down from a warm 77.2°F (25.1°C) in August to a pleasant 70.7°F (21.5°C). During September, the average low-temperature is a cool 52°F (11.1°C).Humidity
In September, the average relative humidity is 80%.Rainfall
In Calmar, in September, during 13.3 rainfall days, 2.48" (63mm) of precipitation is typically accumulated. In Calmar, during the entire year, the rain falls for 149 days and collects up to 30.59" (777mm) of precipitation.Snowfall
In Calmar, snow does not fall in June through September.Daylight
In September, the average length of the day is 12h and 29min.On the first day of the month, sunrise is at 6:32 am and sunset at 7:41 pm. On the last day of September, in Calmar, sunrise is at 7:04 am and sunset at 6:49 pm CDT.
Sunshine
In Calmar, the average sunshine in September is 8.9h.UV index
In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for the average person.Note: In September, the maximum UV index of 4 transforms into these recommendations:
Undertake protective steps - Obligation to safeguard skin and eyes from harm is in place. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. A hat with a broad brim is indispensable, filtering out up to half of UV rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Calmar, IA
- Average high temperature in September: 70.7°F
The warmest month (with the highest average high temperature) is July (78.4°F).
The month with the lowest average high temperature is January (22.3°F).
- Average low temperature in September: 52°F
The month with the highest average low temperature is July (61.9°F).
The coldest month (with the lowest average low temperature) is January (9.7°F).
Average pressure in September
Calmar, IA
- Average pressure in September: 30.02"Hg
The months with the highest atmospheric pressure are January and February (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in September
Calmar, IA
- Average wind speed in September: 8.1mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (7mph).
Average humidity in September
Calmar, IA
- Average humidity in September: 80%
The months with the highest relative humidity are January and February (89%).
The month with the lowest relative humidity is October (76%).
Average rainfall in September
Calmar, IA
- Average rainfall in September: 2.48"
The wettest month (with the highest rainfall) is June (5.04").
The driest month (with the least rainfall) is January (1.1").
Average rainfall days in September
Calmar, IA
- Average rainfall days in September: 13.3 days
The months with the highest number of rainy days are May and June (20.3 days).
The month with the least rainy days is February (4.4 days).
Average snowfall in September
Calmar, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (5.98").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Calmar, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (14.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Calmar, IA
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in September: 8h and 54min
The month with the most sunshine is August (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).
Average sunshine days in September
Calmar, IA
- Average sunshine days in September: 14.5 days
The month with the most sunshine days is November (16.2 days).
The month with the least sunshine days is June (7.1 days).
Average UV index in September
Calmar, IA
- Average UV index in September: 4
The months with the highest UV index are May, June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 1).
Average cloud cover in September
Calmar, IA
- Average cloud cover in September: 33
The month with the most cloud cover is January (Cloud cover 64).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in September
Calmar, IA
- Average visibility in September: 6mi
The months with the highest visibility are March, April, May, June, August, September, October and November (6mi).
The months with the lowest visibility are January, February, July and December (5mi).
