Des Moines, IA weather in September
Expect mild weather with some rain in Des Moines in September, with highs near 77°F and lows near 55°F. Rain falls on about 8 days. Good for outdoor plans.
- Normal high
- 77°F
- Normal low
- 55°F
- Wet days
- 8
- 3.2 in total
- Muggy days
- 4
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 81°F | 71°F |
| Normal low | 61°F | 50°F |
| Chance of a wet day | 28% | 28% |
| Sunrise / sunset | 6:40 am / 7:48 pm | 7:10 am / 6:58 pm |
| Daylight | 13.1 h | 11.8 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Central Time).
A typical September day
- 6 am58°Fdew point 53°F
- 9 am65°Fdew point 55°F
- Noon73°Fdew point 55°F
- 3 pm75°Fdew point 55°F
- 6 pm71°Fdew point 55°F
- 9 pm65°Fdew point 55°F
NOAA hourly normals (local standard time) from Des Moines Intl Airport (5 mi away); average wind 9 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F14 of 30
- Hot dayshigh 90°F or more2 of 30
- Muggy daysdaily mean dew point 65°F or more4 of 30
- Wet daysat least 0.01 in of rain or melted snow8 of 30
- Notable rainat least 0.10 in5 of 30
- Freezing nightslow 32°F or below0 of 30
- Snow on the groundsnow depth 1 in or more0 of 30
Average days per September, counted from daily records for each year 1991-2020.
Rain in September
Normal precipitation is 3.2 in; a dry September brings about 1.5 in and a wet one about 4.2 in (25th and 75th percentiles). About 2 days bring half an inch or more, and about 1 an inch or more.
How September varies from year to year
- Warmest September, 1991-20202013: average high 83°F
- Coolest September1993: average high 69°F
- Wettest September2018: 8.3 in
- Driest September1998: 0.7 in
- Highest reading101°F (September 9, 2013)
- Lowest reading31°F (September 22, 1995)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
September compared with August and October
| August | September | October | |
|---|---|---|---|
| Normal high | 84°F | 77°F | 63°F |
| Normal low | 64°F | 55°F | 43°F |
| Wet days | 9 | 8 | 9 |
| Comfortable days | 5 | 14 | 12 |
| Daylight | 13.8 h | 12.5 h | 11.1 h |
Highs change by -7°F from August and -14°F into October.
Nearby alternatives in September
- Cooler: Rochester, MN177 mi · high 72°F · 9 wet days
How Des Moines ranks in September
- Normal high245th warmest of 378 cities; 3rd of 3 in Iowa
- Wet days206th driest of 378
- Comfortable days112th most of 342
What to pack for Des Moines in September
- A rain jacket or umbrella – rain on about 8 days
Heating and cooling
September has 86 heating degree days and 120 cooling degree days (base 65°F), 3% of the year's total heating and cooling demand.
Questions
How hot is Des Moines in September?
The normal high is 77°F and the normal low is 55°F. From 1991 to 2020 the hottest September reading was 101°F (September 9, 2013).
Does it rain a lot in Des Moines in September?
About 8 days in September have at least 0.01 in of precipitation, and the normal total is 3.2 in. The wettest September in 1991-2020 was in 2018 (8.3 in); the driest was in 1998 (0.7 in).
Is September a good time to visit Des Moines?
September ranks 2nd of 12 months on our comfort score for Des Moines (66 out of 100). It has about 14 comfortable days and about 2 days at 90°F or hotter. The best month is May.
Where the numbers come from
- Temperature, rain, snowfall, snow depth, frost dates and humidity and wind by hour: Des Moines Intl Airport (USW00014933), 5.1 mi SSW of the city center, 957 ft (85 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Des Moines International Airport (725460-14933), 5.1 mi SSW of the city center, 939 ft (67 ft higher than the city). Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).