Weather in Des Moines in August

A good month. August is a solid month to be in Des Moines. Highs average 29.5 °C, lows 17.7 °C, and rain falls on 12 days — nothing in the month is working against you.

August ranks 6 of 12 in Des Moines: past the worst of the year but short of September, which is the month to book if the dates are open.

Rain on 12 days, 4 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 29.5 °C days and 17.7 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 13 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest August day reached 41.2 °C and the coldest night fell to 8.1 °C, and the wettest single day dropped 45 mm — roughly 41% of the month's rain in one day.

August is moderately variable: 22 mm in the driest year against 239 mm in the wettest, around an average of 110 mm. Roughly two Augusts in three land near that average, and the third does something else entirely.

Wind is light at 8.5 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 69%.

How August sits in the year

Temperatures hold steady either side: 30.5 °C in July, 29.5 here, 25.6 in September. Nothing about the timing within the month matters much.

Daylight in August

13.9 hours of daylight, losing 1.2 hours across the month. That is between Des Moines's extremes of 15.2 and 9.2 hours, so days are long enough not to constrain the plan.

An inland climate

Des Moines has no sea to moderate it, and it shows: 40.3 °C separates the hottest afternoon of the year from the coldest night. That is a genuinely continental range, and it means summer and winter here are barely the same place.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

August in Des Moines versus nearby

If Des Moines is one option among several, the nearby comparison is worth making. Omaha is close enough to be a coin toss — within a degree on temperature, the same number of rain days. Kansas City is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: August works, with September the better month by 16 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Des Moines

See all twelve months in Des Moines, or where else to go in August.