September weather forecast and climate
Des Moines, IA

City buildings in Des Moines, Iowa
City buildings in Des Moines, Iowa
The first month of the autumn, September, is still a warm month in Des Moines, Iowa, with temperature in the range of an average high of 75.6°F (24.2°C) and an average low of 55.9°F (13.3°C).

Temperature

In September, the average high-temperature marginally drops, from 81.7°F (27.6°C) in August, to a still warm 75.6°F (24.2°C). In Des Moines, in September, the average low-temperature is 55.9°F (13.3°C).

Humidity

The average relative humidity in September is 76%.

Rainfall

In Des Moines, Iowa, during September, the rain falls for 10.5 days and regularly aggregates up to 1.73" (44mm) of precipitation. In Des Moines, during the entire year, the rain falls for 114.4 days and collects up to 16.38" (416mm) of precipitation.

Snowfall

In Des Moines snow does not fall in June through September.

Daylight

In Des Moines, the average length of the day is 12.5h.

Sunshine

In September, the average sunshine is 9.3h.

UV index

The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from the exposure to the Sun's UV radiation for the average person.
Note: The daily maximum UV index of 4 in September interpret into the following advice:
Take precautions - Protection against sun damage is advised. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.

What is the temperature in September in Des Moines?

The average high-temperature, in September, in Des Moines, Iowa, is 75.6°F (24.2°C), while the average low-temperature is 55.9°F (13.3°C).

What is the average humidity in September in Des Moines?

In September, the average relative humidity in Des Moines, Iowa, is 76%.

How many days does it rain in September in Des Moines?

In Des Moines, in September, it is raining for 10.5 days, with typically 1.73" (44mm) of accumulated precipitation.

Does it snow in Des Moines in September?

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

When it does not snow in Des Moines?

In Des Moines, Iowa, snow does not fall in June through September.

What is the average length of the day in September in Des Moines?

The average length of the day in September in Des Moines, Iowa, is 12.5h.

How long on average sun shines in September in Des Moines?

In September, the average sunshine in Des Moines is 9.3h.

How high is the UV index in September in Des Moines?

In Des Moines, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate vulnerability from the exposure to the Sun's UV rays.
Average temperature in September - Des Moines, IA
  • Average high temperature in September: 75.6°F

The warmest month (with the highest average high temperature) is July (83.1°F).
The month with the lowest average high temperature is January (28.2°F).

  • Average low temperature in September: 55.9°F

The month with the highest average low temperature is July (65.5°F).
The coldest month (with the lowest average low temperature) is January (15.1°F).

Average pressure in September - Des Moines, IA
  • Average pressure in September: 30.01"

The month with the highest atmospheric pressure is January (30.16").
The month with the lowest atmospheric pressure is June (29.88").

Average wind speed in September - Des Moines, IA
  • Average wind speed in September: 8mph

The windiest months (with the highest average wind speed) are January, February, March and April (10.3mph).
The calmest months (with the lowest average wind speed) are July and August (7mph).

Average humidity in September - Des Moines, IA
  • Average humidity in September: 76%

Months with the highest relative humidity are January and June (82%).
The month with the lowest relative humidity is October (70%).

Average rainfall in September - Des Moines, IA
  • Average rainfall in September: 1.73"

The wettest month (with the highest rainfall) is May (2.76").
The driest month (with the least rainfall) is January (0.47").

Average rainfall days in September - Des Moines, IA
  • Average rainfall days in September: 10.5 days

The month with the highest number of rainy days is June (15.9 days).
The month with the least rainy days is February (3 days).

Average snowfall in September - Des Moines, IA
  • Average snowfall in September: 0"

The month with the highest snowfall is January (2.24").
Months with the least snowfall are June, July, August and September (0").

Average snowfall days in September - Des Moines, IA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (8.7 days).
Months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September / Average sunshine in September - Des Moines, IA
  • Average daylight in September: 12.5h

The month with the longest days is June (Average daylight: 15.2h).
The month with the shortest days is December (Average daylight: 9.2h).

  • Average sunshine in September: 9.3h

The month with the most sunshine is July (Average sunshine: 10.3h).
The month with the least sunshine is January (Average sunshine: 4.3h).

Average sunshine days in September - Des Moines, IA
  • Average sunshine days in September: 17.5 days

The month with the most sunshine days is December (22.3 days).
The month with the least sunshine days is June (12.2 days).

Average UV index in September - Des Moines, IA
  • Average UV index in September: 4

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 - Des Moines, IA
  • Average cloud cover in September: 29

The month with the most cloud cover is January (Cloud cover 54).
Months with the least cloud cover are July and September (Cloud cover 29).

Average visibility in September - Des Moines, IA
  • Average visibility in September: 6mi

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