Des Moines weather in August: Des Moines, Iowa: normal highs, lows, rain and records for August
Des Moines in August has a normal high of 84°F and a normal low of 64°F, a daily mean of 74°F, falling from 85°F on the 1st to 81°F by the 31st. Measurable precipitation falls on 9 days in a normal August, 4.17 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 29°C and low of 18°C, 106 mm of precipitation in August.
- NOAA stationDes Moines International Airport
- Station IDUSW00014933
- Location41.53°N 93.65°W
- Elevation957 ft (292 m)
- From the center3 miles
- Population213,096
- Jan 31° 14°
- Feb 36° 18°
- Mar 49° 30°
- Apr 62° 41°
- May 72° 52°
- Jun 82° 62°
- Jul 86° 66°
- Aug 84° 64°
- Sep 77° 55°
- Oct 63° 43°
- Nov 48° 30°
- Dec 36° 20°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Des Moines in August?
The normal high is 84°F and the normal low 64°F, for a daily mean of 73.9°F. August is 2.1°F cooler than July and 7.7°F warmer than September. August is the 2nd warmest month of the year in Des Moines and the 3rd wettest. Across the month the normal high falls 4°F, from 85°F on August 1 to 81°F on August 31. From one year to the next August's mean temperature typically moves about 2.4°F either way (NOAA's standard deviation), so roughly two Augusts in three average between 72°F and 76°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 31%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| August 1 | 85°F | 66°F | 31% | 21% |
| August 8 | 85°F | 66°F | 31% | 21% |
| August 15 | 84°F | 65°F | 30% | 21% |
| August 22 | 83°F | 63°F | 29% | 19% |
| August 31 | 81°F | 61°F | 29% | 18% |
Every day of August: normal high, low and chance of precipitation (warmest afternoon August 1, coldest night August 31)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| August 1 | 85°F | 66°F | 31% | 21% | 14 h 30 min |
| August 2 | 85°F | 66°F | 31% | 21% | 14 h 20 min |
| August 3 | 85°F | 66°F | 31% | 21% | 14 h 20 min |
| August 4 | 85°F | 66°F | 31% | 21% | 14 h 20 min |
| August 5 | 85°F | 66°F | 31% | 21% | 14 h 20 min |
| August 6 | 85°F | 66°F | 31% | 21% | 14 h 10 min |
| August 7 | 85°F | 66°F | 31% | 21% | 14 h 10 min |
| August 8 | 85°F | 66°F | 31% | 21% | 14 h 10 min |
| August 9 | 85°F | 66°F | 31% | 21% | 14 h 10 min |
| August 10 | 84°F | 65°F | 31% | 21% | 14 h 10 min |
| August 11 | 84°F | 65°F | 31% | 21% | 14 h |
| August 12 | 84°F | 65°F | 31% | 21% | 14 h |
| August 13 | 84°F | 65°F | 30% | 21% | 14 h |
| August 14 | 84°F | 65°F | 30% | 21% | 14 h |
| August 15 | 84°F | 65°F | 30% | 21% | 13 h 50 min |
| August 16 | 84°F | 65°F | 30% | 20% | 13 h 50 min |
| August 17 | 84°F | 64°F | 30% | 20% | 13 h 50 min |
| August 18 | 84°F | 64°F | 30% | 20% | 13 h 50 min |
| August 19 | 83°F | 64°F | 30% | 20% | 13 h 40 min |
| August 20 | 83°F | 64°F | 29% | 20% | 13 h 40 min |
| August 21 | 83°F | 64°F | 29% | 20% | 13 h 40 min |
| August 22 | 83°F | 63°F | 29% | 19% | 13 h 40 min |
| August 23 | 83°F | 63°F | 29% | 19% | 13 h 30 min |
| August 24 | 83°F | 63°F | 29% | 19% | 13 h 30 min |
| August 25 | 83°F | 63°F | 29% | 19% | 13 h 30 min |
| August 26 | 82°F | 62°F | 29% | 19% | 13 h 30 min |
| August 27 | 82°F | 62°F | 29% | 19% | 13 h 20 min |
| August 28 | 82°F | 62°F | 29% | 19% | 13 h 20 min |
| August 29 | 82°F | 62°F | 29% | 19% | 13 h 20 min |
| August 30 | 82°F | 61°F | 29% | 19% | 13 h 20 min |
| August 31 | 81°F | 61°F | 29% | 18% | 13 h 10 min |
- Normal high
- 84°FAugust average
- Normal low
- 64°FAugust average
- Precipitation
- 4.17 inmonth total
- Days with precipitation
- 90.01 inch or more
- Days at 90°F or more
- 6
- Daylight
- 14 h 30 min to 13 h 10 minAugust 1 to August 31
- Days at 70°F or more
- 31
- Days at 80°F or more
- 23
- Sunshine
- 80%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00014933; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Des Moines in August?
On a given August day the chance of 0.01 inch or more is 30% on average, highest around August 1 (31%). In all, 4.17 in falls on 9 days of a normal August, 1 of them with an inch or more.
In a normal August in Des Moines, 6 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00014933.
How humid and windy is Des Moines in August?
At 3 p.m. the normal temperature is 81°F with 51% relative humidity and a dew point of 62°F; at 6 a.m. it is 64°F with 86% humidity. The wind averages 7.9 mph, most often from the south in the afternoon.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 64°F | 60°F | 86% | 6.2 mph | 46% |
| 9 a.m. | 72°F | 62°F | 71% | 8.5 mph | 53% |
| noon | 79°F | 62°F | 57% | 9.9 mph | 40% |
| 3 p.m. | 81°F | 62°F | 51% | 10.2 mph | 45% |
| 6 p.m. | 78°F | 62°F | 58% | 8.1 mph | 49% |
| 9 p.m. | 72°F | 62°F | 71% | 7.1 mph | 65% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00014933. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for August in Des Moines?
The warmest August temperature on Des Moines's official record (since 1878) is 110°F, on August 4, 1918; the coldest is 40°F, on August 24, 1891. The wettest August brought 13.68 in (1977).
The August mean against the 1991-2020 normal of 73.9°F: 2021 76.4°F (+2.5), 2022 76.1°F (+2.2), 2023 75.9°F (+2.0), 2024 75.0°F (+1.1), 2025 73.7°F (−0.2), 2026 75.2°F (+1.3). 5 of 6 ran warmer than normal.
| August | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 76.4°F | +2.5°F | 2.13 in |
| 2022 | 76.1°F | +2.2°F | 4.04 in |
| 2023 | 75.9°F | +2.0°F | 2.40 in |
| 2024 | 75.0°F | +1.1°F | 2.90 in |
| 2025 | 73.7°F | −0.2°F | 1.96 in |
| 2026 | 75.2°F | +1.3°F | 5.83 in |
Source: records: ACIS, NWS threaded record DSMthr; recent months: ACIS, station USW00014933. Records and recent months use complete months only.
How does August in Des Moines compare across Iowa?
Across the 132 places PlainClimate covers in Iowa, August normal highs run from 76°F in Northwood to 85°F in Donnellson; Des Moines's is 84°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.