Weather in St. Louis in July

Shoulder season. July sits in between. You will get good days and you will lose some. Highs average 31.2 °C, lows 20.4 °C, and rain falls on 13 days — nothing in the month is working against you.

July ranks 9 of 12 in St. Louis: past the worst of the year but short of October, which is the month to book if the dates are open.

Rain on 13 days, 4 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 31.2 °C days and 20.4 °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: 20 days top 30 °C, making the heat continuous rather than occasional. Across the twenty years measured, the hottest July day reached 42.6 °C and the coldest night fell to 12.2 °C, and the wettest single day dropped 51 mm — roughly 50% of the month's rain in one day.

July is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest July on record still delivered 172 mm against 34 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 101 mm average is a reasonable planning figure, not a promise.

Wind is light at 5.6 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 74%.

How July sits in the year

Temperatures hold steady either side: 28.9 °C in June, 31.2 here, 31 in August. Nothing about the timing within the month matters much.

Daylight in July

July is at or near the longest days of St. Louis's year: 14.6 hours of daylight, losing 0.6 hours across the month. Evenings are the real gain — dinner outdoors still happens in full light.

An inland climate

With no coast nearby, the year swings a fair way — 36.6 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

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

July in St. Louis versus nearby

If St. Louis is one option among several, the nearby comparison is worth making. Indianapolis is a better bet in July — 2.8 °C cooler, 1 day more rain. Kansas City is close enough to be a coin toss — within a degree on temperature, 2 days less rain.

So: July is a compromise. October is 26 points better and is what St. Louis is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in St. Louis

See all twelve months in St. Louis, or where else to go in July.