Mercer County weather alerts
There are no active weather alerts for Mercer County, IL right now.
Since 2016 the National Weather Service has issued about 907 alerts that included Mercer County, roughly 91 a year. The most common is the severe thunderstorm warning (170 from 2016 to 2025). The last tornado warning was issued on July 20, 2026. 46 tornadoes have touched down in the county since 1950.
Updated from the National Weather Service · lists refresh hourly; the live map loads current alerts directly from the NWS
No warnings, watches or advisories include Mercer County at the moment. This page updates automatically when the National Weather Service issues one. Check neighboring Knox County, Henry County, Des Moines County, Warren County.
Mercer County alert history
Alert events that included Mercer County or its forecast zones, from the NWS warning archive.
| Alert type | 2016–2025 | 2026 | Last issued |
|---|---|---|---|
| Severe Thunderstorm Warning | 170 | 30 | September 20, 2026 |
| Dense Fog Advisory | 100 | 5 | September 11, 2026 |
| Winter Weather Advisory | 96 | 1 | March 16, 2026 |
| Wind Advisory | 71 | 5 | April 2, 2026 |
| Flood Warning | 65 | 6 | October 2, 2026 |
| Severe Thunderstorm Watch | 63 | 12 | August 21, 2026 |
| Heat Advisory | 50 | 5 | August 31, 2026 |
| Flood Watch | 45 | 10 | September 30, 2026 |
| Cold Weather Advisory | 37 | 3 | January 26, 2026 |
| Tornado Warning | 28 | 4 | July 20, 2026 |
| Tornado Watch | 26 | 8 | June 11, 2026 |
| Freeze Warning | 21 | 1 | April 20, 2026 |
| Frost Advisory | 18 | 2 | October 17, 2026 |
| Winter Storm Watch | 18 | 1 | March 16, 2026 |
| Winter Storm Warning | 17 | 0 | November 29, 2025 |
| Red Flag Warning | 16 | 3 | March 28, 2026 |
| Extreme Heat Warning | 12 | 3 | September 2, 2026 |
| Flash Flood Warning | 11 | 7 | September 20, 2026 |
| Extreme Heat Watch | 8 | 2 | July 27, 2026 |
| Freeze Watch | 7 | 0 | October 16, 2024 |
| Extreme Cold Warning | 5 | 1 | January 23, 2026 |
| High Wind Warning | 5 | 2 | March 15, 2026 |
| High Wind Watch | 4 | 0 | December 15, 2021 |
| Extreme Cold Watch | 4 | 1 | January 23, 2026 |
| Snow Squall Warning | 3 | 0 | February 19, 2022 |
| Fire Weather Watch | 3 | 2 | February 27, 2026 |
| Blizzard Warning | 2 | 1 | March 16, 2026 |
| Ice Storm Warning | 2 | 0 | December 14, 2024 |
Tornado history in Mercer County
46 tornadoes have been recorded in Mercer County since 1950, injuring 6 people. That ranks 23 of 102 counties in Illinois. The most recent was on June 3, 2025 (rated EF1).
Strongest tornadoes in Mercer County
| Date | Rating | County | Path length | Width | Deaths | Injuries |
|---|---|---|---|---|---|---|
| June 14, 1974 | F3 | Rock Island County | 48.6 mi | 440 yd | 0 | 2 |
| August 15, 1978 | F3 | Mercer County | 6.4 mi | 77 yd | 0 | 0 |
| April 21, 1973 | F2 | Mercer County | 30.2 mi | 10 yd | 0 | 2 |
| May 24, 2015 | EF2 | Mercer County | 6.8 mi | 50 yd | 0 | 0 |
| June 18, 1998 | F2 | Mercer County | 6 mi | 880 yd | 0 | 0 |
Most recent tornadoes
| Date | Rating | County | Path length | Width | Deaths | Injuries |
|---|---|---|---|---|---|---|
| June 3, 2025 | EF1 | Mercer County | 3.8 mi | 100 yd | 0 | 0 |
| June 3, 2025 | EF1 | Mercer County | 10.8 mi | 250 yd | 0 | 0 |
| June 3, 2025 | EF1 | Mercer County | 1.6 mi | 175 yd | 0 | 0 |
| April 20, 2025 | EF0 | Mercer County | 0.9 mi | 25 yd | 0 | 0 |
| July 15, 2024 | EF1 | Rock Island County | 24.7 mi | 100 yd | 0 | 0 |
About Mercer County
- Population: 15,292 (2024 estimate)
- State: Illinois
- NOAA Weather Radio SAME code: 017131 (how to use it)