September weather forecast
Calmar, IA

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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

In Calmar, the average high-temperature in September slightly decreases from a warm 77.2°F (25.1°C) in August to an agreeable 70.7°F (21.5°C). September brings an average low-temperature of 52°F (11.1°C) to Calmar.

Humidity

In Calmar, the average relative humidity in September is 80%.

Rainfall

In Calmar, in September, it is raining for 13.3 days, with typically 2.48" (63mm) of accumulated precipitation. 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

The average length of the day in September is 12h and 29min.
On the first day of September, sunrise is at 6:32 am and sunset at 7:41 pm. On the last day of the month, sunrise is at 7:04 am and sunset at 6:49 pm CDT.

Sunshine

In Calmar, Iowa, 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 threat to health from unsafe exposure to UV radiation for the ordinary person.
Note: In September, the UV index of 4 transforms into the following advice:
Ensure safety - Sun damage prevention is strongly urged. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. Enhance your sun protection with tightly woven, yet airy clothing.
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Frequently asked questions

What is the usual temperature for Calmar in September?

In September, the average high-temperature and low-temperature in Calmar are 70.7°F (21.5°C) and 52°F (11.1°C) respectively.

What is the average humidity in September in Calmar?

In September, the average relative humidity in Calmar is 80%.

How many days does it rain in September in Calmar?

In September, in Calmar, the rain falls for 13.3 days. Throughout September, 2.48" (63mm) of precipitation is accumulated.

When it does not snow in Calmar?

June through September are months without snowfall in Calmar, Iowa.

Does it snow in Calmar in September?

In Calmar, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September in Calmar?

The average day length in September in Calmar, Iowa, is 12h and 29min.

When is the sunrise / sunset in September in Calmar?

In September, on the first day of the month, sunrise is at 6:32 am and sunset at 7:41 pm. On the last day of the month, sunrise is at 7:04 am and sunset at 6:49 pm CDT.

How long on average sun shines in September in Calmar?

The average sunshine duration in September is 8.9h.

What is the UV index intensity in September in Calmar?

In Calmar, Iowa, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium hazard to health from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Calmar, IA

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).

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Average pressure in September
Calmar, IA

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).

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Average wind speed in September
Calmar, IA

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).

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Average humidity in September
Calmar, IA

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%).

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Average rainfall in September
Calmar, IA

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").

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Average rainfall days in September
Calmar, IA

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).

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Average snowfall in September
Calmar, IA

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").

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Average snowfall days in September
Calmar, IA

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).

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Average daylight in September /
Average sunshine in September
Calmar, IA

Average daylight in September / Average sunshine in September - Calmar, IA
  • Average daylight in September: 12h and 3min

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 5min

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).

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Average sunshine days in September
Calmar, IA

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).

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Average UV index in September
Calmar, IA

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).

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Average cloud cover in September
Calmar, IA

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).

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Average visibility in September
Calmar, IA

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).

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Calmar, Iowa, USA

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