September weather forecast
Monmouth, IA

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Weather in September

The first month of the autumn, September, is still a warm month in Monmouth, Iowa, with an average temperature ranging between min 54.5°F (12.5°C) and max 73.6°F (23.1°C).

Temperature

September signifies a gentle decline in Monmouth's average high-temperature, easing from 79.3°F (26.3°C) in August to a still moderately hot 73.6°F (23.1°C). An average low-temperature of 54.5°F (12.5°C) is recorded during the nights in September.

Humidity

In September, the average relative humidity is 78%.

Rainfall

In Monmouth, in September, during 11.6 rainfall days, 2.44" (62mm) of precipitation is typically accumulated. Throughout the year, there are 143.3 rainfall days, and 29.76" (756mm) of precipitation is accumulated.

Snowfall

May through September are months without snowfall.

Daylight

In Monmouth, the average length of the day in September is 12h and 28min.
On the first day of September, sunrise is at 6:29 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:46 pm CDT.

Sunshine

In Monmouth, the average sunshine in September is 9.2h.

UV index

In Monmouth, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: In September, the maximum UV index of 4 suggests these recommendations:
Be mindful. Those with pale skin might receive burns in fewer than 30 minutes. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. 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.
Updated: Aug 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

The high-temperature, in September, in Monmouth, is 73.6°F (23.1°C), while the low-temperature averages to 54.5°F (12.5°C).

What is the average humidity in September?

In September, the average relative humidity is 78%.

How much does it rain in September?

In Monmouth, during September, the rain falls for 11.6 days and regularly aggregates up to 2.44" (62mm) of precipitation.

When it does not snow?

In Monmouth, snow does not fall in May through September.

Does it snow in September?

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

How many hours of daylight does Monmouth have in September?

The average day length in September is 12h and 28min.

When are sunrise and sunset in September?

On the first day of September, sunrise is at 6:29 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:46 pm CDT.

How many hours of sunshine does Monmouth have in September?

In Monmouth, the average sunshine duration in September is 9.2h.

How high is the UV index in September?

In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a moderate vulnerability from unsafe exposure to Sun's UV rays.
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
Monmouth, IA

Average temperature in September - Monmouth, IA
  • Average high temperature in September: 73.6°F

The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (25.9°F).

  • Average low temperature in September: 54.5°F

The month with the highest average low temperature is July (63.7°F).
The coldest month (with the lowest average low temperature) is January (13.3°F).

Average pressure in September
Monmouth, IA

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

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).

Average wind speed in September
Monmouth, IA

Average wind speed in September - Monmouth, IA
  • Average wind speed in September: 7.8mph

The windiest month (with the highest average wind speed) is April (10.5mph).
The calmest months (with the lowest average wind speed) are July and August (6.8mph).

Average humidity in September
Monmouth, IA

Average humidity in September - Monmouth, IA
  • Average humidity in September: 78%

The month with the highest relative humidity is January (86%).
The month with the lowest relative humidity is October (74%).

Average rainfall in September
Monmouth, IA

Average rainfall in September - Monmouth, IA
  • Average rainfall in September: 2.44"

The wettest month (with the highest rainfall) is May (4.53").
The driest month (with the least rainfall) is January (1.34").

Average rainfall days in September
Monmouth, IA

Average rainfall days in September - Monmouth, IA
  • Average rainfall days in September: 11.6 days

The month with the highest number of rainy days is May (18.7 days).
The month with the least rainy days is February (5.3 days).

Average snowfall in September
Monmouth, IA

Average snowfall in September - Monmouth, IA
  • Average snowfall in September: 0"

The month with the highest snowfall is January (5.2").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Monmouth, IA

Average snowfall days in September - Monmouth, IA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (11 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
Monmouth, IA

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

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in September: 9h and 1min

The month with the most sunshine is July (Average sunshine: 9h and 54min).
The months with the least sunshine are January and February (Average sunshine: 3h and 54min).

Average sunshine days in September
Monmouth, IA

Average sunshine days in September - Monmouth, IA
  • Average sunshine days in September: 16.3 days

The month with the most sunshine days is November (18.6 days).
The month with the least sunshine days is May (10.2 days).

Average UV index in September
Monmouth, IA

Average UV index in September - Monmouth, IA
  • Average UV index in September: 4

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

Average cloud cover in September
Monmouth, IA

Average cloud cover in September - Monmouth, IA
  • Average cloud cover in September: 31

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 31).

Average visibility in September
Monmouth, IA

Average visibility in September - Monmouth, IA
  • Average visibility in September: 6mi

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

Monmouth, Iowa, USA

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