| NWS Forecast for: Grafton IL Issued by: National Weather Service Saint Louis, MO Last Update: 11:51 am CDT Sep 4, 2026 |  |
This Afternoon: Sunny and hot, with a high near 99. Heat index values as high as 104. Southwest wind 5 to 7 mph. Tonight: Mostly clear, with a low around 76. Light and variable wind. Saturday: Sunny and hot, with a high near 100. Heat index values as high as 105. Calm wind becoming west around 5 mph in the afternoon. Saturday Night: Mostly clear, with a low around 73. Northeast wind 3 to 6 mph. Sunday: Sunny, with a high near 93. Northeast wind 5 to 8 mph. Sunday Night: Partly cloudy, with a low around 68. Labor Day: Sunny, with a high near 91. Monday Night: Mostly clear, with a low around 69. Tuesday: Sunny and hot, with a high near 97. Tuesday Night: Mostly clear, with a low around 76. Wednesday: Sunny and hot, with a high near 99. Wednesday Night: A 20 percent chance of showers and thunderstorms. Mostly clear, with a low around 76. Thursday: A 20 percent chance of showers and thunderstorms. Sunny, with a high near 94. | |
| Grafton IL 38.98°N 90.44°W (Elev. 515 ft) | |
Visit your local NWS office at: https://www.weather.gov/lsx/ |
