St. Louis wakes up under clear skies on Thursday, June 18, 2026, with temperatures hovering near 72°F and a sticky, humid feel close to the river. As the day goes on, skies turn partly sunny with just a slight chance of brief afternoon showers, and the high is expected to top out near 79°F.
Afternoon Spotty Showers
Most of the day should stay dry, but a few light showers could pop up between noon and 5 p.m., especially around the I-70 corridor. Northwest winds are expected to remain light at 3 to 8 mph, and tonight’s low should slip to around 61°F. Coverage looks limited and any rain should be short lived, so most commutes will likely move along without much trouble, but keep an umbrella handy just in case, according to the National Weather Service St. Louis.
Juneteenth And Weekend Outlook
Friday, June 19 (Juneteenth) is on track to be mostly sunny with a warm high near 85°F, although patchy morning fog could linger in low-lying river valleys before about 7 a.m. Saturday should run a bit warmer, and the pattern turns more unsettled late Saturday night into Sunday, when showers and thunderstorms are most likely. There is a low threat for locally heavy downpours on Sunday, so it could turn into a wet stretch for some neighborhoods rather than a steady all day washout. If you are planning outdoor celebrations, line up a backup plan and keep an eye on local listings through the City of St. Louis event calendar.
Plan Ahead
If you have outdoor plans this afternoon or over the holiday weekend, bring a light rain layer and allow a few extra minutes for travel during peak shower windows. Keep tabs on forecast updates through the day and into the weekend in case storm timing or coverage shifts.
