McHenry County weather alerts
There are no active weather alerts for McHenry County, IL right now.
Since 2016 the National Weather Service has issued about 895 alerts that included McHenry County, roughly 90 a year. The most common is the severe thunderstorm warning (132 from 2016 to 2025). The last tornado warning was issued on April 18, 2026. 29 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 McHenry County at the moment. This page updates automatically when the National Weather Service issues one. Check neighboring DeKalb County, Kenosha County, Kane County, Cook County.
McHenry County alert history
Alert events that included McHenry County or its forecast zones, from the NWS warning archive.
| Alert type | 2016–2025 | 2026 | Last issued |
|---|---|---|---|
| Severe Thunderstorm Warning | 132 | 23 | August 21, 2026 |
| Dense Fog Advisory | 109 | 10 | October 23, 2026 |
| Flood Advisory | 91 | 5 | September 20, 2026 |
| Winter Weather Advisory | 90 | 2 | March 16, 2026 |
| Severe Thunderstorm Watch | 69 | 12 | August 21, 2026 |
| Wind Advisory | 61 | 6 | June 28, 2026 |
| Flood Warning | 47 | 3 | April 18, 2026 |
| Flood Watch | 42 | 7 | September 19, 2026 |
| Cold Weather Advisory | 37 | 3 | January 26, 2026 |
| Frost Advisory | 27 | 3 | May 7, 2026 |
| Freeze Warning | 24 | 2 | October 17, 2026 |
| Winter Storm Warning | 21 | 0 | November 29, 2025 |
| Flash Flood Warning | 20 | 2 | June 11, 2026 |
| Tornado Watch | 19 | 4 | June 11, 2026 |
| Winter Storm Watch | 18 | 0 | November 29, 2025 |
| Heat Advisory | 16 | 5 | September 4, 2026 |
| Tornado Warning | 15 | 3 | April 18, 2026 |
| High Wind Warning | 11 | 2 | April 27, 2026 |
| Freeze Watch | 9 | 1 | April 20, 2026 |
| Red Flag Warning | 6 | 1 | February 18, 2026 |
| Extreme Heat Watch | 5 | 0 | July 23, 2025 |
| Extreme Heat Warning | 5 | 2 | July 27, 2026 |
| High Wind Watch | 5 | 1 | March 13, 2026 |
| Extreme Cold Warning | 5 | 1 | January 23, 2026 |
| Fire Weather Watch | 4 | 1 | February 18, 2026 |
| Ice Storm Warning | 2 | 0 | February 22, 2023 |
| Extreme Cold Watch | 2 | 1 | January 23, 2026 |
| Snow Squall Warning | 2 | 0 | February 19, 2022 |
| Blizzard Warning | 1 | 1 | March 16, 2026 |
Tornado history in McHenry County
29 tornadoes have been recorded in McHenry County since 1950, killing 32 people and injuring 637. That ranks 51 of 102 counties in Illinois. The most recent was on May 7, 2024 (rated EF0).
Strongest tornadoes in McHenry County
| Date | Rating | County | Path length | Width | Deaths | Injuries |
|---|---|---|---|---|---|---|
| April 21, 1967 | F4 | Boone County | 25.5 mi | 1,200 yd | 24 | 450 |
| April 11, 1965 | F4 | McHenry County | 9.1 mi | 400 yd | 6 | 75 |
| April 21, 1967 | F4 | McHenry County | 8.8 mi | 150 yd | 1 | 100 |
| January 7, 2008 | EF3 | Boone County | 13.1 mi | 100 yd | 0 | 5 |
| October 8, 1958 | F2 | Stephenson County | 81 mi | 10 yd | 1 | 0 |
Most recent tornadoes
| Date | Rating | County | Path length | Width | Deaths | Injuries |
|---|---|---|---|---|---|---|
| May 7, 2024 | EF0 | McHenry County | 14.3 mi | 50 yd | 0 | 0 |
| July 12, 2023 | EF0 | McHenry County | 3.4 mi | 125 yd | 0 | 0 |
| July 12, 2023 | EF1 | McHenry County | 6.4 mi | 200 yd | 0 | 0 |
| May 31, 2023 | ? | McHenry County | 0.6 mi | 25 yd | 0 | 0 |
| August 9, 2021 | EF1 | McHenry County | 0.4 mi | 70 yd | 0 | 0 |
About McHenry County
- Population: 315,959 (2024 estimate)
- State: Illinois
- NOAA Weather Radio SAME code: 017111 (how to use it)