Sioux City, Iowa – Dangerous heat is gripping northwest Iowa Monday, where heat index values as high as 108 degrees are expected this afternoon under an Extreme Heat Warning that remains in effect through 9 p.m. Monday, creating a heightened risk for heat-related illnesses.
According to the National Weather Service in Sioux Falls, air temperatures climbing into the 90s combined with oppressive humidity will push apparent temperatures into the 100- to 108-degree range across northwest Iowa. Communities including Le Mars, Sheldon, Spencer, Storm Lake, Cherokee and surrounding areas face the greatest heat threat. Portions of southwest Minnesota are under a Heat Advisory, while southeastern South Dakota will also experience dangerous afternoon heat.
The most hazardous conditions are expected during the afternoon and early evening, when prolonged exposure or strenuous outdoor activity can quickly lead to heat exhaustion or heat stroke. Residents planning to work outside should adjust schedules, take frequent breaks in air-conditioned locations and drink water regularly, even before feeling thirsty.
Travelers along U.S. Highway 75, U.S. Highway 20 and Iowa Highway 60 should also be prepared for extreme conditions if spending extended time outdoors. Never leave children or pets unattended inside vehicles, where temperatures can become life-threatening within minutes.
The Extreme Heat Warning remains in effect through 9 p.m. Monday, and additional heat headlines may be needed if dangerous heat persists into the week. Continue monitoring updates from the National Weather Service and local emergency officials.
Five-Day Forecast for Sioux City, Iowa
- Monday: High in the low 90s. Peak heat index 100°-108°. Dangerous afternoon heat.
- Tuesday: High in the low 90s. Continued hot and humid with heat indices near 100°.
- Wednesday: Warm and humid with highs in the upper 80s to low 90s.
- Thursday: Seasonably warm with highs in the 80s and a lower heat risk.
- Friday: Warm summer conditions continue with highs in the 80s.
