Louisville is heading into a sharp temperature swing: Sunday’s forecast calls for a sunny afternoon near 96 degrees, with heat-index values approaching 100, followed by rain chances Monday and a cooler pattern beginning Tuesday.
Sunday brings the week’s peak heat
The day will start in the mid-70s under clear skies before sunshine pushes temperatures toward 96 degrees. Southwest winds are expected to remain light, around 5 to 10 mph. People spending time outdoors should drink water, take breaks in shade or air conditioning, and avoid strenuous activity during the hottest part of the day.
A slight chance of showers is expected Sunday night, with partly cloudy skies and a low near 71. Monday brings a higher chance of showers and thunderstorms, a high near 87, and another round of storms Monday night before cooler air arrives.
Comparable late-September heat has happened before
A forecast near 96 degrees would be notably hot for late September, but it would not be without precedent. The National Weather Service Louisville office recorded a 95-degree high in Louisville on both September 27 and September 28, 2019, followed by a 98-degree high on September 30.
That same month also shows why individual comparisons should be used carefully. Louisville recorded 22 days in the 90s during September 2019, a monthly record, according to the National Weather Service. Those records establish that comparable heat has occurred before; they do not, by themselves, show that hot late-September days are becoming more frequent.
Heat illness can develop quickly
The temperature is more than a comfort issue, especially for people outdoors for long periods. Kentucky’s 2022 Action Plan identifies headaches, dizziness, and fainting as possible signs of heat exhaustion and warns that prolonged exposure can lead to heatstroke. Water, shade, air conditioning, and reduced exertion during peak heat can help limit exposure.
Cooler air arrives after Monday
Tuesday is forecast to remain unsettled, with a chance of rain and a high near 77. The rest of the week is expected to be much milder, with highs in the mid-70s and overnight lows falling into the upper 50s and mid-50s. The exact timing and strength of the rain and temperature change can still shift as the forecast is updated.
