Hurricanes and Tornadoes That Hit Dennis Port, MA

The nearest NOAA station with 1991–2020 climate normals is Chatham Municipal Airport, MA, 8 miles east of Dennis Port at 68 feet. July is the warmest, with an average high of 79°F and low of 64°F; January is the coolest, at 39°F and 26°F. December is the wettest at 5.0 inches of precipitation on average and July the driest at 2.8 inches; the year adds up to 45.2 inches over 80 days with at least a tenth of an inch. June to November, the hurricane season months, bring 47% of the year's precipitation (21.1 of 45.2 inches); the other six months are wetter. September has brought the most of the 63 tropical systems that passed within 75 miles (20); a normal September there has highs of 71°F and 3.6 inches of precipitation. Highs reach 90°F on about 1 days a year. Lows fall below freezing on about 92 nights a year. That 45.2 inches is more than at 13 of the 65 Massachusetts stations used on this site (20%). South Yarmouth, 3 miles west, has its own station (Hyannis Barnstable Municipal Airport, MA): 44.8 inches a year, 0.4 less than here, and a July average high of 81°F against 79°F.

Water temperature at the NOAA tide station Chatham, MA, 10 miles east, averaged 69°F in August and 39°F in February over 2021–2025. No month averaged 80°F. Sea level at the Nantucket Island tide gauge, 26 miles from Dennis Port, has risen 1.63 ± 0.06 inches per decade from 1965 to 2025, NOAA's linear trend; at that pace it is 16.3 inches in a hundred years. That is faster than at 101 of the 144 U.S. gauges with a NOAA trend.

Since 1996, the National Weather Service has logged 56 flood, rain, thunderstorm wind and lightning events that began within 10 miles of Dennis Port: 24 thunderstorm wind reports, 21 floods, 6 flash floods, 4 lightning strikes and 1 heavy rain event. None is recorded as killing or injuring anyone; the NWS estimated $3.9 million in property and crop damage. The strongest thunderstorm gust on record here was 90 mph, on July 23, 2019. August has had the most flash floods, 4 of 6. Of the 339 Massachusetts cities on this site with a flash flood on record, 52 have had fewer than Dennis Port.

Flood insurance policyholders in Dennis Port's ZIP code 02639 have filed 111 claims with the National Flood Insurance Program since 1978, and were paid $991,000 for buildings and contents, in the dollars of each year. The most came from Hurricane Bob in 1991: 32 claims (29% of all) and $435,000, then Flooding in 1996 with 12 and December Nor'easter in 2023 with 11. 53% of the claims carry the name of a storm or flood event; the rest have no event name. Of the 229 Massachusetts cities on this site with 10 or more claims, 169 have fewer than Dennis Port.