Des Moines
Iowa, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Des Moines, IA

A close view of city buildings in Des Moines, Iowa
A close view of city buildings in Des Moines, Iowa
September, the first month of the autumn, in Des Moines, is also a moderately hot month, with average temperature varying between 76.1°F (24.5°C) and 55.2°F (12.9°C).

Temperature

In September, the average high-temperature slightly decreases, from 83.8°F (28.8°C) in August, to a still warm 76.1°F (24.5°C). In September, the average low-temperature is 55.2°F (12.9°C).

Humidity

In September, the average relative humidity in Des Moines, Iowa, is 70.9%.

Rainfall

In Des Moines, during September, the rain falls for 8.4 days and regularly aggregates up to 3.1" (77.5mm) of precipitation. Throughout the year, there are 113.4 rainfall days, and 36" (914.9mm) of precipitation is accumulated.

Snowfall

In Des Moines, it doesn't snow. In October, it regularly snows. In Des Moines, during the entire year, snow aggregates up to 35.3" (896.7mm).

Daylight

In September, the average length of the day is 12.5h.

Sunshine

In Des Moines, the average sunshine is 8h.

UV index

In September, the average daily maximum UV index is 6. A UV Index value of 6 to 7 symbolizes a high health hazard from the exposure to the Sun's UV rays for the average person.
In September, the average maximum UV index of 6 translate into the following recommendations:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. 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?

In Des Moines, Iowa, in September, the average high-temperature is 76.1°F (24.5°C), and the average low-temperature is 55.2°F (12.9°C).

What is the average humidity in September in Des Moines?

The average relative humidity in September in Des Moines is 70.9%.

How much does it rain in Des Moines in September?

In September, in Des Moines, Iowa, the rain falls for 8.4 days. Throughout September, 3.1" (77.5mm) of precipitation is accumulated.

Does it snow in Des Moines in September?

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

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

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

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

In September, the average sunshine in Des Moines is 8h.

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

The average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health threat from the exposure to the Sun's UV rays.
Average temperature in September - Des Moines, IA
  • Average high temperature in September: 76.1°F

The warmest month (with the highest average high temperature) is July (85.7°F).
The month with the lowest average high temperature is January (31°F).

  • Average low temperature in September: 55.2°F

The month with the highest average low temperature is July (66.8°F).
The coldest month (with the lowest average low temperature) is January (14.3°F).

Average humidity in September - Des Moines, IA
  • Average humidity in September: 70.9%

The month with the highest relative humidity is December (74.6%).
The month with the lowest relative humidity is May (63%).

Average rainfall in September - Des Moines, IA
  • Average rainfall in September: 3.1"

The wettest month (with the highest rainfall) is June (4.9").
The driest month (with the lowest rainfall) is January (1").

Average rainfall days in September - Des Moines, IA
  • Average rainfall days in September: 8.4 days

The month with the highest number of rainy days is May (12.5 days).
The month with the lowest number of rainy days is January (7.5 days).

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

The month with the highest snowfall is December (9").
Months with the lowest snowfall are May, 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 (6.5 days).
Months with the lowest number of snowfall days are May, 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 shortest days is December (Average daylight: 9.2h).

  • Average sunshine in September: 8h

The month with most sunshine is July (Average sunshine: 10.9h).
The month with least sunshine is December (Average sunshine: 4.2h).

Average UV index in September - Des Moines, IA
  • Average UV index in September: 6

Months with the highest UV index are June and July (UV index 9).
Months with the lowest UV index are January and December (UV index 1).