| NWS Forecast for: Washington County Issued by: National Weather Service Saint Louis, MO Last Update: 1042 PM CDT Sat Aug 15 2026 |  |
Overnight: Partly cloudy. A slight chance of showers and thunderstorms. Lows in the mid 70s. Southwest winds around 5 mph. Chance of rain 20 percent. Sunday: Mostly sunny with a slight chance of showers and thunderstorms. Humid with highs in the mid 90s. West winds around 5 mph. Gusts up to 20 mph in the morning. Chance of rain 20 percent. Heat index values up to 110. Sunday Night: Partly cloudy in the evening, then becoming mostly cloudy. A chance of showers and thunderstorms. Humid with lows around 70. North winds around 5 mph. Gusts up to 20 mph in the evening. Chance of rain 40 percent. Heat index values up to 105 early in the evening. Monday: Mostly sunny. Highs in the mid 80s. North winds 5 to 10 mph. Monday Night: Partly cloudy in the evening, then becoming mostly clear. Lows in the mid 60s. Northeast winds around 5 mph in the evening, becoming light and variable. Tuesday: Sunny. Highs in the lower 90s. Tuesday Night And Wednesday: Partly cloudy. A slight chance of showers and thunderstorms. Lows in the lower 70s. Highs in the lower 90s. Chance of rain 20 percent. Heat index values up to 100. Wednesday Night: Partly cloudy with a slight chance of showers and thunderstorms in the evening, then mostly cloudy with a chance of showers and thunderstorms after midnight. Lows in the mid 60s. Chance of rain 40 percent. Thursday: Partly sunny with a slight chance of thunderstorms. A chance of showers, mainly in the morning. Highs in the lower 80s. Chance of rain 40 percent. Thursday Night: Partly cloudy with a slight chance of showers and thunderstorms. Lows in the mid 60s. Chance of rain 20 percent. Friday: Mostly sunny. A slight chance of showers in the morning. Highs in the mid 80s. Chance of rain 20 percent. Friday Night And Saturday: Partly cloudy. Lows in the mid 60s. Highs in the mid 80s. | |
| Zone Forecast: Washington County | |
Visit your local NWS office at: https://www.weather.gov/lsx/ |