St. Mary's County weather alerts
There are no active weather alerts for St. Mary's County, MD right now.
Since 2016 the National Weather Service has issued about 1,355 alerts that included St. Mary's County, roughly 136 a year. The most common is the coastal flood advisory (423 from 2016 to 2025). The last tornado warning was issued on August 20, 2026. 34 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 St. Mary's County at the moment. This page updates automatically when the National Weather Service issues one. Check neighboring Calvert County, Charles County.
St. Mary's County alert history
Alert events that included St. Mary's County or its forecast zones, from the NWS warning archive.
| Alert type | 2016–2025 | 2026 | Last issued |
|---|---|---|---|
| Coastal Flood Advisory | 423 | 3 | October 23, 2026 |
| Severe Thunderstorm Warning | 234 | 31 | August 23, 2026 |
| Severe Thunderstorm Watch | 93 | 19 | October 16, 2026 |
| Coastal Flood Warning | 76 | 2 | September 27, 2026 |
| Wind Advisory | 69 | 2 | March 16, 2026 |
| Flood Watch | 61 | 1 | July 6, 2026 |
| Flood Warning | 59 | 0 | January 10, 2024 |
| Heat Advisory | 59 | 8 | September 3, 2026 |
| Dense Fog Advisory | 35 | 1 | March 5, 2026 |
| Winter Weather Advisory | 29 | 0 | December 6, 2025 |
| Tornado Warning | 26 | 3 | August 20, 2026 |
| Frost Advisory | 22 | 1 | April 9, 2026 |
| Tornado Watch | 22 | 3 | August 20, 2026 |
| Flash Flood Warning | 20 | 1 | July 6, 2026 |
| Extreme Heat Warning | 15 | 3 | July 4, 2026 |
| Freeze Warning | 14 | 1 | April 21, 2026 |
| Winter Storm Warning | 13 | 2 | February 22, 2026 |
| Extreme Heat Watch | 12 | 2 | July 4, 2026 |
| Winter Storm Watch | 12 | 2 | February 22, 2026 |
| Freeze Watch | 11 | 1 | April 21, 2026 |
| Fire Weather Watch | 9 | 0 | November 16, 2025 |
| Red Flag Warning | 9 | 0 | November 16, 2025 |
| Cold Weather Advisory | 9 | 8 | February 7, 2026 |
| High Wind Warning | 8 | 1 | February 7, 2026 |
| Tropical Storm Warning | 6 | 0 | September 21, 2023 |
| High Wind Watch | 4 | 0 | February 16, 2025 |
| Tropical Storm Watch | 3 | 0 | July 7, 2021 |
| Blizzard Warning | 1 | 0 | January 22, 2016 |
| Ice Storm Warning | 1 | 0 | February 13, 2021 |
Tornado history in St. Mary's County
34 tornadoes have been recorded in St. Mary's County since 1950, injuring 4 people. That ranks 2 of 24 counties in Maryland. The most recent was on July 1, 2025 (rated EF1).
Strongest tornadoes in St. Mary's County
| Date | Rating | County | Path length | Width | Deaths | Injuries |
|---|---|---|---|---|---|---|
| October 13, 1983 | F2 | St. Mary's County | 4 mi | 37 yd | 0 | 0 |
| September 5, 1979 | F1 | St. Mary's County | 17.8 mi | 50 yd | 0 | 0 |
| June 27, 2015 | EF1 | Charles County | 16.1 mi | 800 yd | 0 | 0 |
| May 27, 2022 | EF1 | St. Mary's County | 4.1 mi | 100 yd | 0 | 0 |
| April 28, 2011 | EF1 | St. Mary's County | 3.4 mi | 150 yd | 0 | 0 |
Most recent tornadoes
| Date | Rating | County | Path length | Width | Deaths | Injuries |
|---|---|---|---|---|---|---|
| July 1, 2025 | EF1 | St. Mary's County | 1 mi | 100 yd | 0 | 0 |
| June 8, 2022 | EF0 | St. Mary's County | 3 mi | 75 yd | 0 | 0 |
| May 27, 2022 | EF1 | St. Mary's County | 4.1 mi | 100 yd | 0 | 0 |
| August 4, 2020 | EF0 | St. Mary's County | 5.2 mi | 100 yd | 0 | 0 |
| August 4, 2020 | EF0 | St. Mary's County | 1.5 mi | 75 yd | 0 | 0 |
About St. Mary's County
- Population: 116,469 (2024 estimate)
- State: Maryland
- NOAA Weather Radio SAME code: 024037 (how to use it)