Des Moines weather in September

In September, Des Moines sees average daytime highs of 76°F and overnight lows near 55°F, with 3.5 in of rain across 8 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 80°F in the first days to 71°F by the end. The sky is clear or mostly clear about 48% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Des Moines's 1st-clearest and 9th-windiest month. For the whole year in context, see Des Moines's year-round climate.

Daytime high
76°
4th warmest
Overnight low
55°
9th coldest
Rainfall
3.5 in
8 wet days
Daylight
12 h 18 min
6:01 AM – 6:17 PM
Cloud cover
45%
1st clearest
Wind
8 mph
9th windiest
Solar energy
4.65 kWh/m²
Travel score
7.2
out of 10

Des Moines is capital city of the U.S. state of Iowa and seat of Polk County.

Density
911/km²
people per km²
Founded
1843

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 80°F in the first days to 71°F by the end.

A typical September day in Des Moines reaches about 76°F in the afternoon and slips back to 55°F overnight — a 20°F spread between the day's warmth and the night's chill. On most days the high lands between 64°F and 86°F. Set against its neighbours, September runs about 7°F cooler than August and about 13°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18161
28161
38060
48060
58060
67959
77959
87858
97858
107858
117757
127757
137656
147656
157656
167555
177555
187554
197454
207454
217453
227353
237352
247352
257251
267251
277151
287150
297150
307049

How September really feels in Des Moines

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Des Moines weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan30° / 14°1.26.34.69.30.0
Feb35° / 18°1.56.34.710.30.0
Mar48° / 30°2.68.82.511.71.9
Apr61° / 41°4.211.20.913.14.8
May71° / 53°5.313.60.114.36.1
Jun81° / 63°4.911.60156.1
Jul84° / 67°3.69.4014.75.7
Aug82° / 64°3.79.5013.76.4
Sep76° / 55°3.58012.37.2
Oct63° / 43°2.87.80.310.95.8
Nov48° / 31°2.06.81.39.72.0
Dec35° / 20°1.65.93.990.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 48% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 37%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16733
26733
36634
46634
56634
66535
76535
86436
96436
106337
116337
126238
136238
146139
156040
166040
176040
186040
196040
206040
216040
226139
236139
246139
256238
266238
276238
286238
296238
306337

Chance of precipitation in September

Any precipitation

Des Moines gets around 3.5 in of rain over 8 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 27% and peaks near 30% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
125
225
325
425
525
625
726
826
927
1027
1128
1228
1329
1430
1530
1630
1730
1830
1930
2030
2129
2229
2328
2428
2527
2627
2727
2826
2926
3026

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 49% of days. Sticky, muggy-or-worse air turns up on roughly 15% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1212223259
2232223238
3252323228
4272323207
5292322196
6322322185
7342321175
8362321164
9382220164
10402220153
11422219153
12432218142
13452118142
14472117132
15482116131
16512016121
17522015121
18542014111
19561913111
20581912101
21581912101
2261181191
2363181081
246617980
256717970
267016860
277016860
287315750
297315750
307514650

Wind in September

Winds average 8 mph in September.

Across September, daily wind ranges from about 8 mph on the calmest days to 9 mph at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (mph)Feels
18light breeze
28light breeze
38light breeze
48light breeze
58light breeze
68light breeze
78light breeze
88light breeze
98light breeze
108light breeze
118light breeze
128light breeze
138light breeze
148light breeze
158light breeze
169light breeze
179light breeze
189light breeze
199light breeze
209light breeze
219light breeze
229light breeze
239light breeze
249light breeze
259light breeze
269light breeze
279light breeze
289light breeze
299light breeze
309light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 hours at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 84 minutes over September. Sunrise moves from 5:45 AM to 6:16 AM, and sunset from 6:44 PM to 5:52 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:456:44
212.95:466:42
312.95:476:40
412.85:486:38
512.85:496:37
612.75:506:35
712.75:516:33
812.75:526:31
912.65:536:30
1012.65:546:28
1112.55:556:26
1212.55:566:24
1312.45:576:22
1412.45:586:21
1512.35:596:19
1612.36:016:17
1712.26:026:15
1812.26:036:13
1912.16:046:12
2012.16:056:10
2112.06:066:08
2212.06:076:06
2311.96:086:04
2411.96:096:03
2511.86:106:01
2611.86:115:59
2711.76:125:57
2811.76:135:55
2911.76:145:54
3011.66:165:52

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.65 kWh/m².

For context, solar energy here swings from a low near 1.81 kWh/m² to a high of 6.46 kWh/m² in July across the year — September's 4.65 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.3Bright
25.2Bright
35.2Bright
45.2Bright
55.1Bright
65.1Bright
75.0Bright
85.0Bright
94.9Bright
104.9Bright
114.8Bright
124.8Bright
134.7Bright
144.7Bright
154.6Bright
164.6Bright
174.5Bright
184.5Bright
194.4Bright
204.4Bright
214.3Bright
224.3Bright
234.3Bright
244.2Bright
254.2Bright
264.2Bright
274.1Bright
284.1Bright
294.0Bright
304.0Moderate
Planning a trip in September

Is September a good time to visit Des Moines?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

7.2
Sightseeing
1st-best month of the year
6.1
Beach & pool
4th-best month of the year

September is one of the better times to visit Des Moines for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Des Moines in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Des Moines sees daytime highs around 76°F and nights near 55°F. Worth packing: light clothes, rain gear and sun protection. About 8 days see rain.

light clothesrain gearsun protection

UV index in Des Moines in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Des Moines peaks around June 20 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJun 20UV 9Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May7High
Jun9Very high
Jul9Very high
Aug7Very high
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Des Moines in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Des Moines is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (October, 7 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateGoodJul 1915 µg/m³Oct 217 µg/m³
PM2.5 (µg/m³)Level
Jan12Moderate
Feb14Moderate
Mar13Moderate
Apr10Good
May11Good
Jun12Moderate
Jul16Moderate
Aug14Moderate
Sep12Good
Oct7Good
Nov8Good
Dec10Good
Location & terrain

Where is Des Moines?

Des Moines sits at 41.6°N, 93.6°W, 873 ft above sea level, in United States. The nearest listed city is West Des Moines, 5.6 mi away.

Topography around Des Moines

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Des Moines.

Within 2 miles, the terrain around Des Moines has only modest variations in elevation — a maximum elevation change of 200 ft around an average of 840 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 276 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 758 ft.

The land around Des Moines is covered by artificial surfaces (51%) and trees (30%) within 2 miles, trees (33%), grassland (23%) and cropland (21%) within 10 miles, and cropland (62%) and grassland (20%) within 50 miles.

2 miles
200 ft
10 miles
276 ft
50 miles
758 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: West Des Moines 5.6 mi · Urbandale 5.6 mi · Clive 6.2 mi · Johnston 6.8 mi · Altoona 8.1 mi · Ankeny 8.7 mi · Waukee 14 mi · Indianola 17 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Des Moines (41.6005°, -93.6091°, elevation 873 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).