Weather in St. Louis in April

A good month. April works. It is not the peak, but nothing about it fights you. Highs average 19.6 °C, lows 7.1 °C, and rain falls on 11 days — nothing in the month is working against you.

April ranks 3 of 12 in St. Louis. Only October scores clearly higher, and the difference is small enough to be settled by price rather than weather.

Rain on 11 days, 4 of them heavy. Enough to need a plan B, not enough to need a plan around it. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: it never really gets hot: not one day in an average April reaches 30 °C; 3 nights fall below freezing. Across the twenty years measured, the hottest April day reached 30.1 °C and the coldest night fell to -6.1 °C, and the wettest single day dropped 66 mm — roughly 55% of the month's rain in one day.

April is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest April on record still delivered 248 mm against 63 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 121 mm average is a reasonable planning figure, not a promise.

Wind is light at 9.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 76%, high enough to notice on the warm days without dominating them.

How April sits in the year

The month is on the way up: 6.4 °C warmer than March, and May adds another 4.5 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in April

13.2 hours of daylight, gaining 1.2 hours across the month. That is between St. Louis's extremes of 14.8 and 9.5 hours, so days are long enough not to constrain the plan.

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

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.

April in St. Louis versus nearby

If St. Louis is one option among several, the nearby comparison is worth making. Indianapolis is close enough to be a coin toss — 2.4 °C cooler, 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: April is effectively as good as it gets here — 5 points behind October, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in St. Louis

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