Pennsylvania sees a moderate amount of severe weather each year, with 1,047 confirmed tornadoes, 5,341 hailstorm events and 22,001 damaging-wind events recorded by the National Weather Service since 1950., and averages 14 tornadoes per year over the 75-year record. Pennsylvania combines a continental severe-weather season with lake-effect winter storms, giving it one of the most varied weather climates in the country. The interactive map below plots every significant severe-weather event in Pennsylvania from the official NOAA Storm Events Database (1950 through September 2025).
Use the map to find your county, click any marker for the date, magnitude, and casualty details of that event, and switch between tornadoes, hail and wind using the chips. For the national view across all 50 states, see our NOAA Storm Reports interactive map. For tornado tracks specifically, see the US Tornado Tracks map; for hail size and frequency, the US Hailstorms map.
Pennsylvania Severe Weather by the Numbers (1950–2025)
- 1,047 tornadoes recorded between 1950 and 2025
- 258 violent tornadoes rated F2/EF2 or stronger
- 2 confirmed F5/EF5 tornadoes on record — the maximum rating on the Fujita and Enhanced Fujita scales
- 83 direct tornado deaths and 1,306 direct injuries
- 5,341 hailstorm events recorded by the NWS
- 22,001 damaging-wind events on record
- 14 tornadoes per year on average across the 75-year record
- July is the peak severe-weather month, accounting for roughly 21.9% of Pennsylvania tornadoes
- 753 total direct deaths from all severe-weather event types tracked by the NWS
When Pennsylvania Severe Weather Happens
Pennsylvania tornado activity peaks in spring, with March through June accounting for about 49% of all events. The single busiest month is July, which alone produces around 21.9% of recorded tornadoes.
- July: 229 tornadoes (21.9%) — peak month
- May: 200 tornadoes (19.1%)
- June: 197 tornadoes (18.8%)
- August: 125 tornadoes (11.9%)
- April: 88 tornadoes (8.4%)
- September: 80 tornadoes (7.6%)
Top 10 Pennsylvania Counties by Tornado Frequency
Tornado activity in Pennsylvania is geographically broad, but a handful of counties have logged many times the state average. The combination of population density (more spotters and damage reports), county land area and local climatology drives the rankings below.
| County | Tornadoes since 1950 |
|---|---|
| Westmoreland | 46 |
| Crawford | 39 |
| Lancaster | 36 |
| York | 32 |
| Bucks | 29 |
| Chester | 29 |
| Lycoming | 29 |
| Allegheny | 27 |
| Berks | 27 |
| Butler | 26 |
The Deadliest Tornadoes in Pennsylvania History
Pennsylvania has lost 83 lives to tornadoes since the National Weather Service began systematic tornado record-keeping in 1950. The single deadliest event killed 12 people in Erie County in 1985, rated F4 on the Fujita scale.
| Date | Location | Rating | Direct deaths | Direct injuries |
|---|---|---|---|---|
| May 31, 1985 | Erie County | F4 | 12 | 82 |
| May 31, 1985 | Crawford County | F4 | 8 | 75 |
| May 31, 1985 | Venango County | F4 | 8 | 40 |
| May 31, 1985 | Mercer County | F5 | 8 | 60 |
| May 31, 1985 | Forest County | F4 | 7 | 30 |
| May 31, 1985 | Butler County | F3 | 6 | 80 |
| May 31, 1985 | McKean County | F4 | 4 | 40 |
| May 31, 1985 | Beaver County | F3 | 3 | 40 |
| July 27, 1994 | Montgomery County | F3 | 3 | 25 |
| August 3, 1963 | Allegheny County | F3 | 2 | 70 |
Pennsylvania Tornado Strength Distribution
Most Pennsylvania tornadoes are weak: roughly 75% are rated F0/EF0 or F1/EF1. Violent tornadoes (F2+/EF2+) account for around 25% of rated tornadoes in the state. Pennsylvania is one of the few states with a confirmed F5 or EF5 tornado on record.
- F0/EF0 (weak): 276 tornadoes — 26.8% of rated events
- F1/EF1: 496 tornadoes — 48.2% of rated events
- F2/EF2 (strong): 199 tornadoes — 19.3% of rated events
- F3/EF3: 35 tornadoes — 3.4% of rated events
- F4/EF4 (violent): 22 tornadoes — 2.1% of rated events
- F5/EF5 (incredible): 2 tornadoes — 0.2% of rated events
Record-Setting Severe Weather in Pennsylvania
Largest hailstone: 4.50 inches in diameter, observed in Beaver County on July 26, 1956. The three largest hailstones on record in Pennsylvania measured 4.50″, 4.00″, 4.00″.
Highest measured wind gust: 80 knots (92 mph) recorded in Washington County near West Alexander on July 25, 2005. Most damaging-wind events in Pennsylvania are estimated rather than measured because anemometers are sparse across the rural areas where supercells most often produce destructive thunderstorm winds.
How Pennsylvania Compares Nationally
Pennsylvania ranks 26th nationally for tornado frequency, in the middle of the pack of US states by severe-weather activity.
- Tornadoes (top 5): Texas (9,908), Kansas (4,890), Oklahoma (4,856), Florida (3,779), Iowa (3,417).
- Pennsylvania tornado total: 1,047 — ranked 26th nationally.
- Pennsylvania hail total: 5,341 hail events on record since 1950.
- Pennsylvania wind total: 22,001 damaging-wind events on record since 1950.
Frequently Asked Questions
How many tornadoes does Pennsylvania have on average per year?
Pennsylvania averages 14 tornadoes per year over the 1950–2025 period. Counts vary widely year to year, but the long-term mean over 75 years of NWS records is a reliable benchmark for typical activity.
What was the deadliest tornado in Pennsylvania history?
The May 31, 1985 tornado, rated F4 on the Fujita scale, killed 12 people and injured 82 in Erie County. It remains the single deadliest tornado in the Pennsylvania modern record.
Where in Pennsylvania are tornadoes most common?
The single county with the most tornadoes on record is Westmoreland County with 46 events. The three most active counties overall are Westmoreland, Crawford, Lancaster.
How does Pennsylvania compare to its neighbors?
Pennsylvania shares a severe-weather climate with New York, New Jersey, Delaware, Maryland, West Virginia, Ohio. Severe storms regularly cross state lines, so the same supercells, hail cores and wind events often appear in Pennsylvania’s neighbors’ records on the same date.
How recent is the data on this map?
The map and statistics on this page are pulled from NOAA’s official Storm Events Database, which currently runs from January 1950 through September 2025. New records typically appear in the database within 30–90 days of the event date, once damage surveys and ratings are complete.
Compare Pennsylvania to Neighboring States
Severe weather doesn’t stop at state lines. The same supercell systems that produce Pennsylvania tornadoes regularly cross into neighboring states. Compare Pennsylvania’s storm history to its land neighbors:
- New York severe storm history — ranked 30th nationally, Great Lakes severe-weather and lake-effect winters
- New Jersey severe storm history — ranked 36th nationally, Northeast nor’easter corridor
- Delaware severe storm history — ranked 46th nationally
- Maryland severe storm history — ranked 33rd nationally
- West Virginia severe storm history — ranked 38th nationally
- Ohio severe storm history — ranked 22nd nationally, Great Lakes severe-weather and lake-effect winters
Explore the national NOAA Storm Reports map · US Tornado Tracks map · US Hailstorms map
