Hurricanes and Tornadoes That Hit Swarthmore, PA

The nearest NOAA station with 1991–2020 climate normals is Philadelphia International Airport, PA, 6 miles east of Swarthmore at 10 feet. July is the warmest, with an average high of 88°F and low of 70°F; January is the coolest, at 41°F and 26°F. July and September are the wettest at 4.4 inches of precipitation on average and February the driest at 2.8 inches; the year adds up to 44.2 inches over 73 days with at least a tenth of an inch. June to November, the hurricane season months, bring 53% of the year's precipitation (23.5 of 44.2 inches); the other six months are drier. September has brought the most of the 38 tropical systems that passed within 75 miles (15); a normal September there has highs of 79°F and 4.4 inches of precipitation. Highs reach 90°F on about 30 days a year, almost all from May to September. Lows fall below freezing on about 77 nights a year. Snowfall averages 23.1 inches a year, most of it in February. That 44.2 inches is more than at 71 of the 148 Pennsylvania stations used on this site (48%). Wallingford, 1 mile southwest, has its own station (Marcus Hook, PA): 41.8 inches a year, 2.4 less than here, and a July average high of 89°F against 88°F.

Water temperature at the NOAA tide station Marcus Hook, PA, 7 miles southwest, averaged 82°F in July and 39°F in January over 2021–2025. It averaged 80°F or warmer from July to August. Sea level at the Philadelphia tide gauge, 11 miles from Swarthmore, has risen 1.24 ± 0.04 inches per decade from 1900 to 2025, NOAA's linear trend; at that pace it is 12.4 inches in a hundred years. That is faster than at 73 of the 144 U.S. gauges with a NOAA trend.

Since 1996, the National Weather Service has logged 677 flood, rain, thunderstorm wind and lightning events that began within 10 miles of Swarthmore: 429 thunderstorm wind reports, 168 flash floods, 52 floods, 20 lightning strikes and 8 heavy rain events. They killed 7 people and injured 34, and the NWS estimated $74.3 million in property and crop damage. The strongest thunderstorm gust on record here was 105 mph, on April 4, 2025. August has had the most flash floods, 56 of 168. Of the 788 Pennsylvania cities on this site with a flash flood on record, 723 have had fewer than Swarthmore.

Flood insurance policyholders in Swarthmore's ZIP code 19081 have filed 31 claims with the National Flood Insurance Program since 1978, and were paid $232,000 for buildings and contents, in the dollars of each year. 32% of the claims carry the name of a storm or flood event; the rest have no event name. Of the 553 Pennsylvania cities on this site with 10 or more claims, 194 have fewer than Swarthmore.