NHC HURDAT2 · SPC Tornado Database
Hurricanes and Tornadoes That Hit Knox, PA
Every tropical system within 75 miles since 1851 and every tornado within 25 miles since 1950.
Data: NOAA NHC HURDAT2 and NOAA SPC tornado and hail reports, through 2025 · Updated
10 tropical systems have passed within 75 miles of Knox, Pennsylvania since 1851, 0 of them at hurricane strength; the most recent was Sandy in 2012. Since 1950, 39 tornadoes have touched down within 25 miles, 2 of them rated EF3 or stronger.
- Hurricanes
- 0
- Tropical storms
- 10
- Tornadoes
- 39
- EF3 or stronger
- 2
within 75 mi, since 1851
below hurricane strength
within 25 mi, since 1950
25 deaths in all
What the records show for Knox
None of the 10 tropical systems was at hurricane strength as it passed Knox; the strongest was an unnamed storm in 1896, a tropical storm with 61 mph winds when its centre passed 36 miles away. The record near Knox begins with an unnamed storm in 1878; the most recent system was Sandy in 2012, a tropical storm 34 miles away. Of the 10 systems, 2 have come since 2000. Of the 794 Pennsylvania cities on this site, 73% have more tropical storms and hurricanes within 75 miles than Knox. The highest rating among the 39 tornadoes within 25 miles is F4, reached 2 times; the most recent, on May 31, 1985, came within 14 miles. Of the 39, 2 had paths within 5 miles of the city centre, and 21 have come since 2000. May has had the most tornadoes, 11. The most recent tornado was on June 9, 2025. Of the 794 Pennsylvania cities, 82% have more tornadoes within 25 miles than Knox. Hail has been reported within 10 miles 31 times since 1983, with stones up to 2.5 inches (tennis ball size). Of the 794 Pennsylvania cities, 70% have more hail reports within 10 miles than Knox.
Compare Knox's storm record with another city →
Tropical storms and hurricanes near Knox
| Year | Storm | Closest | Strength when closest | Peak |
|---|---|---|---|---|
| 2012 | SandyOct 31 | 34 mi | Tropical storm (40 mph) | Category 3 |
| 2003 | IsabelSep 19 | 42 mi | Tropical storm (40 mph) | Category 5 |
| 1995 | OpalOct 6 | 72 mi | Tropical storm (46 mph) | Category 4 |
| 1989 | HugoSep 22 | 53 mi | Tropical storm (41 mph) | Category 5 |
| 1955 | ConnieAug 13 | 42 mi | Tropical storm (52 mph) | Category 4 |
| 1928 | Unnamed 1928 stormSep 20 | 34 mi | Tropical storm (40 mph) | Category 5 |
| 1915 | Unnamed 1915 stormOct 1 | 72 mi | Tropical storm (40 mph) | Category 4 |
| 1902 | Unnamed 1902 stormJun 29 | 33 mi | Tropical storm (40 mph) | Category 1 |
| 1896 | Unnamed 1896 stormSep 30 | 36 mi | Tropical storm (61 mph) | Category 3 |
| 1878 | Unnamed 1878 stormSep 13 | 26 mi | Tropical storm (47 mph) | Category 2 |
Strength is the sustained wind on the track at the closest point, which is not the wind felt in Knox: a hurricane's worst winds sit within a few dozen miles of its centre, and inland cities are usually past that.
Tornadoes within 25 miles of Knox
By decade
- 2020s2
- 2010s16
- 2000s3
- 1990s3
- 1980s6(2 EF3+)
- 1970s7
- 1950s2
| Date | Rating | Distance | Path | Killed / injured |
|---|---|---|---|---|
| May 31, 1985 | F4 | 14 mi | 56.2 mi | 16 / 125 |
| May 31, 1985 | F4 | 21 mi | 29 mi | 7 / 30 |
| Jul 11, 1976 | F2 | 19 mi | 28.7 mi | 1 / 7 |
| Oct 2, 2018 | EF2 | 21 mi | 4.09 mi | 0 / 0 |
| Jul 19, 1996 | F2 | 16 mi | 10 mi | 0 / 0 |
| Sep 23, 1986 | F2 | 19 mi | 0.5 mi | 0 / 1 |
| May 31, 1985 | F2 | 7 mi | 6 mi | 0 / 1 |
| Aug 7, 1981 | F2 | 19 mi | 0.1 mi | 0 / 0 |
| Jun 1, 1954 | F2 | in town | 0.1 mi | 0 / 0 |
| Jun 1, 1954 | F2 | 21 mi | 3 mi | 0 / 0 |
| Jul 23, 1978 | F1 | 18 mi | 0.1 mi | 1 / 24 |
| Jun 16, 2019 | EF1 | 12 mi | 1.54 mi | 0 / 0 |
The strongest 12 of 39, by rating and then by deaths. Ratings before February 2007 are on the original Fujita scale.
Hail in Knox
The Storm Prediction Center has 31 hail reports within 10 miles of Knox since 1983, made on 22 separate days. Of these, 15 were 1 inch across or larger, and one reached 2 inches. The largest, 2.5 inches (tennis ball size), fell on August 3, 2015. The most recent report is from May 28, 2019. June has the most reports, 11.
Source: NOAA Storm Prediction Center severe weather reports, data through 2025.
Weather by month in Knox
The nearest NOAA station with 1991–2020 climate normals is Clarion 3 SW, PA, 7 miles southeast of Knox at 1,040 feet. July is the warmest, with an average high of 82°F and low of 57°F; January is the coolest, at 33°F and 16°F. July is the wettest at 5.3 inches of precipitation on average and February the driest at 2.7 inches; the year adds up to 46.9 inches over 101 days with at least a tenth of an inch. June to November, the hurricane season months, bring 54% of the year's precipitation (25.4 of 46.9 inches); the other six months are drier. September has brought the most of the 10 tropical systems that passed within 75 miles (5); a normal September there has highs of 74°F and 4.0 inches of precipitation. Highs reach 90°F on about 9 days a year, almost all from June to August. Lows fall below freezing on about 155 nights a year. That 46.9 inches is more than at 99 of the 148 Pennsylvania stations used on this site (67%). Seneca, 12 miles northwest, has its own station (Franklin, PA): 46.5 inches a year, 0.4 less than here, and a July average high of 83°F against 82°F.
| Month | High °F | Low °F | Precip. in | Days ≥ 0.1" |
|---|---|---|---|---|
| Jan | 33 | 16 | 3.6 | 10 |
| Feb | 36 | 16 | 2.7 | 8 |
| Mar | 46 | 23 | 3.5 | 8 |
| Apr | 60 | 33 | 4.1 | 10 |
| May | 71 | 44 | 3.9 | 8 |
| Jun | 79 | 53 | 4.7 | 9 |
| Jul | 82 | 57 | 5.3 | 8 |
| Aug | 81 | 56 | 4.2 | 8 |
| Sep | 74 | 50 | 4.0 | 8 |
| Oct | 62 | 38 | 3.6 | 8 |
| Nov | 49 | 29 | 3.6 | 8 |
| Dec | 38 | 22 | 3.7 | 9 |
| Year | 59 | 36 | 46.9 | 101 |
Averages for 1991–2020 at Clarion 3 SW, PA (1,040 ft), from NOAA NCEI U.S. Climate Normals. Normals describe the station; the farther a place is from it, and the bigger the difference in height, the more its weather can differ.
Floods, thunderstorm wind and lightning near Knox
Since 1996, the National Weather Service has logged 167 flood, rain, thunderstorm wind and lightning events that began within 10 miles of Knox: 127 thunderstorm wind reports, 26 flash floods, 8 heavy rain events and 6 floods. None is recorded as killing or injuring anyone; the NWS estimated $2.0 million in property and crop damage. The strongest thunderstorm gust on record here was 70 mph, on May 1, 2017. July has had the most flash floods, 11 of 26. Of the 788 Pennsylvania cities on this site with a flash flood on record, 394 have had fewer than Knox.
October 6, 2024: thunderstorm wind 6 miles from the centre of Knox — $1.0 million damage.
NWS: “A tree was reported down along Canoe Ripple Road and Elliot Road.”
July 1, 2023: flash flood 9 miles from the centre of Knox — $100,000 damage.
Source: NOAA NCEI Storm Events Database, events whose starting point is on record, 1996 to June 30, 2026. Damage is the NWS estimate in the dollars of the year, not insured losses, and NWS notes that some reports are unverified.
Flood insurance claims, disaster declarations and FEMA risk ratings
Clarion County, which includes Knox, has been named in 14 federal disaster or emergency declarations since 1972, 9 of them major disasters (by incident: 5 floods, 3 hurricanes, 2 biological emergencies, 2 severe storms). The latest major disaster declaration was Covid-19 Pandemic, on March 30, 2020. FEMA's National Risk Index gives Clarion County a Very Low rating for natural hazard risk overall; by hazard: Relatively Moderate for lightning; Relatively Low for hurricanes, tornadoes, inland flooding and strong wind; Very Low for hail and heat waves. It models the county's expected loss from all 18 hazards it covers at $8.7 million a year, the 61st highest of 67 Pennsylvania counties; of the hazards above, the largest share, $6.2 million (72%), is from inland flooding.
Claims: FEMA, OpenFEMA Dataset FIMA NFIP Redacted Claims – v3, summed over ZIP codes; payments in the dollars of each year, not adjusted for inflation. Declarations: Disaster Declarations Summaries – v2, by county. Retrieved October 25, 2026. This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Risk ratings: FEMA, National Risk Index county table, December 2025 (v1.20), retrieved October 26, 2026; ratings compare counties nationwide, are meant for planning and are no substitute for a local risk assessment. This product uses the Federal Emergency Management Agency's National Risk Index dataset API or downloadable datasets but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
What counts as a pass, the distances and the sources: how this storm history is built.