| NWS Forecast for: Union County Issued by: National Weather Service Sioux Falls, SD Last Update: 114 PM CDT Sat Jul 25 2026 | |
This Afternoon: Mostly sunny. Much warmer with highs in the mid 90s. Southwest winds around 5 mph. Heat index values up to 109. Tonight: Mostly cloudy. A slight chance of showers and thunderstorms after midnight. Humid with lows in the mid 70s. South winds 5 to 10 mph, becoming east with gusts up to 20 mph after midnight. Chance of rain 20 percent. Heat index values up to 108 early in the evening. Sunday: Mostly cloudy in the morning, then becoming mostly sunny. Hot with highs in the upper 90s. South winds 5 to 10 mph with gusts up to 20 mph, increasing to 15 to 20 mph with gusts up to 30 mph in the afternoon. Heat index values up to 108. Sunday Night: Partly cloudy with a chance of showers and thunderstorms in the evening, then mostly clear with a chance of sprinkles after midnight. Humid with lows in the mid 70s. South winds 15 to 20 mph with gusts up to 30 mph, becoming southwest 5 to 10 mph with gusts up to 20 mph after midnight. Chance of rain 30 percent. Heat index values up to 105 early in the evening. Monday: Sunny, hot with highs in the mid 90s. North winds 5 to 10 mph. Monday Night: Mostly clear in the evening, then becoming mostly cloudy. Lows in the lower 70s. Heat index values in the upper 90s early in the evening. Tuesday: Mostly sunny. Highs in the lower 90s. Tuesday Night: Mostly clear. Lows in the upper 60s. Wednesday: Mostly sunny. Highs in the lower 90s. Wednesday Night: Partly cloudy. A chance of showers and thunderstorms after midnight. Lows in the upper 60s. Chance of rain 40 percent. Thursday: Partly sunny. A chance of showers and thunderstorms in the morning. Highs in the lower 90s. Chance of rain 40 percent. Thursday Night: Mostly clear with a chance of showers. A chance of thunderstorms after midnight. Lows in the upper 60s. Chance of rain 40 percent. Friday: Mostly sunny. Highs around 90. | |
| Zone Forecast: Union County | |
Visit your local NWS office at: https://www.weather.gov/fsd/ |