September weather forecast
Mount Union, IA

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Weather in September

The first month of the autumn, September, is still a warm month in Mount Union, Iowa, with an average temperature ranging between max 76.3°F (24.6°C) and min 56.7°F (13.7°C).

Temperature

The transition into September is accompanied by a slight temperature decrease, with the average high-temperature shifting from a warm 81.7°F (27.6°C) in August to a still moderately hot 76.3°F (24.6°C). Mount Union, during the nights of September, experiences an average temperature drop to a moderate 56.7°F (13.7°C).

Humidity

In Mount Union, the average relative humidity in September is 75%.

Rainfall

In September, the rain falls for 11.5 days. Throughout September, 2.56" (65mm) of precipitation is accumulated. Throughout the year, there are 140.1 rainfall days, and 29.92" (760mm) of precipitation is accumulated.

Snowfall

May through September are months without snowfall.

Daylight

In Mount Union, Iowa, the average length of the day in September is 12h and 27min.
On the first day of the month, sunrise is at 6:32 am and sunset at 7:37 pm. On the last day of September, sunrise is at 7:01 am and sunset at 6:48 pm CDT.

Sunshine

In Mount Union, Iowa, the average sunshine in September is 9.3h.

UV index

In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.
Note: In September, the maximum UV index of 4 transforms into these recommendations:
Take precautions - Protection against skin and eye damage is obliged. The Sun's harshest UV rays are around midday; it's wise to seek shade and limit time outdoors. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat.
Updated: Aug 30, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature?

The high-temperature during September is 76.3°F (24.6°C) and the low-temperature is 56.7°F (13.7°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which combines air temperature and relative humidity, in August is computed to be 87.8°F (31°C).

What is the average humidity in September?

In September, the average relative humidity is 75%.

How many days does it rain in September?

In September, the rain falls for 11.5 days. Throughout September, 2.56" (65mm) of precipitation is accumulated.

When it does not snow?

May through September are months without snowfall.

Does it snow in September?

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

How many hours of daylight does Mount Union have in September?

In Mount Union, the average day length in September is 12h and 27min.

When is the sunrise / sunset in September in Mount Union?

In September, on the first day of the month, sunrise is at 6:32 am and sunset at 7:37 pm. On the last day of the month, sunrise is at 7:01 am and sunset at 6:48 pm CDT.

How many hours of sunshine does Mount Union have in September?

The average sunshine duration in September is 9.3h.

What is the UV index reading in September?

In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a medium hazard to health from exposure to the Sun's 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
Mount Union, IA

Average temperature in September - Mount Union, IA
  • Average high temperature in September: 76.3°F

The warmest month (with the highest average high temperature) is July (82.4°F).
The month with the lowest average high temperature is January (29.7°F).

  • Average low temperature in September: 56.7°F

The month with the highest average low temperature is July (65.3°F).
The coldest month (with the lowest average low temperature) is January (17.4°F).

Average pressure in September
Mount Union, IA

Average pressure in September - Mount Union, IA
  • Average pressure in September: 30.02"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).

Average wind speed in September
Mount Union, IA

Average wind speed in September - Mount Union, IA
  • Average wind speed in September: 7.9mph

The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (6.9mph).

Average humidity in September
Mount Union, IA

Average humidity in September - Mount Union, IA
  • Average humidity in September: 75%

The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (71%).

Average rainfall in September
Mount Union, IA

Average rainfall in September - Mount Union, IA
  • Average rainfall in September: 2.56"

The wettest month (with the highest rainfall) is May (4.29").
The driest months (with the least rainfall) are February and December (1.38").

Average rainfall days in September
Mount Union, IA

Average rainfall days in September - Mount Union, IA
  • Average rainfall days in September: 11.5 days

The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is February (4.6 days).

Average snowfall in September
Mount Union, IA

Average snowfall in September - Mount Union, IA
  • Average snowfall in September: 0"

The month with the highest snowfall is January (4.76").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Mount Union, IA

Average snowfall days in September - Mount Union, IA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (9.6 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
Mount Union, IA

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

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).

Average sunshine days in September
Mount Union, IA

Average sunshine days in September - Mount Union, IA
  • Average sunshine days in September: 16.5 days

The month with the most sunshine days is October (18.4 days).
The month with the least sunshine days is May (10.6 days).

Average UV index in September
Mount Union, IA

Average UV index in September - Mount Union, IA
  • Average UV index in September: 4

The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).

Average cloud cover in September
Mount Union, IA

Average cloud cover in September - Mount Union, IA
  • Average cloud cover in September: 31

The month with the most cloud cover is January (Cloud cover 56).
The months with the least cloud cover are July, August and September (Cloud cover 31).

Average visibility in September
Mount Union, IA

Average visibility in September - Mount Union, IA
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).

Mount Union, Iowa, USA

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