Hurricanes and Tornadoes That Hit New Castle, DE

The nearest NOAA station with 1991–2020 climate normals is Wilmington New Castle Co Airport, DE, in New Castle at 79 feet. July is the warmest, with an average high of 87°F and low of 68°F; January is the coolest, at 41°F and 26°F. June is the wettest at 4.7 inches of precipitation on average and February the driest at 2.8 inches; the year adds up to 45.5 inches over 75 days with at least a tenth of an inch. June to November, the hurricane season months, bring 53% of the year's precipitation (24.3 of 45.5 inches); the other six months are drier. September has brought the most of the 40 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 22 days a year, almost all from May to September. Lows fall below freezing on about 92 nights a year. Snowfall averages 20.2 inches a year, most of it in February. That 45.5 inches is more than at 3 of the 11 Delaware stations used on this site (27%). Wilmington, 6 miles north, has its own station (Wilmington Porter Rsch, DE): 50.5 inches a year, 5.0 more than here, and a July average high of 84°F against 87°F.

Water temperature at the NOAA tide station Reedy Point, DE, 8 miles south, averaged 83°F in July and 38°F in January over 2021–2025. It averaged 80°F or warmer from July to August. Sea level at the Reedy Point tide gauge, 8 miles from New Castle, has risen 1.55 ± 0.09 inches per decade from 1956 to 2025, NOAA's linear trend; at that pace it is 15.5 inches in a hundred years. That is faster than at 93 of the 144 U.S. gauges with a NOAA trend.

Since 1996, the National Weather Service has logged 471 flood, rain, thunderstorm wind and lightning events that began within 10 miles of New Castle: 310 thunderstorm wind reports, 76 flash floods, 52 floods, 21 lightning strikes and 12 heavy rain events. They killed 3 people and injured 17, and the NWS estimated $4.9 million in property and crop damage. The strongest thunderstorm gust on record here was 81 mph, on August 7, 2023. July has had the most flash floods, 25 of 76. Of the 37 Delaware cities on this site with a flash flood on record, 32 have had fewer than New Castle.

Flood insurance policyholders in New Castle's ZIP code 19720 have filed 145 claims with the National Flood Insurance Program since 1978, and were paid $1.5 million for buildings and contents, in the dollars of each year. The most came from Hurricane Floyd in 1999: 18 claims (12% of all) and $399,000, then Hurricane Irene in 2011 with 17 and Hurricane Sandy in 2012 with 14. 45% of the claims carry the name of a storm or flood event; the rest have no event name. Of the 24 Delaware cities on this site with 10 or more claims, 14 have fewer than New Castle.