Hurricanes and Tornadoes That Hit Dedham, MA

The nearest NOAA station with 1991–2020 climate normals is Blue Hill Coop, MA, 4 miles southeast of Dedham at 625 feet. July is the warmest, with an average high of 82°F and low of 64°F; January is the coolest, at 35°F and 18°F. March and October are the wettest at 5.5 inches of precipitation on average and July the driest at 3.5 inches; the year adds up to 53.9 inches over 87 days with at least a tenth of an inch. June to November, the hurricane season months, bring 48% of the year's precipitation (25.9 of 53.9 inches); the other six months are wetter. September has brought the most of the 47 tropical systems that passed within 75 miles (18); a normal September there has highs of 73°F and 4.1 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 121 nights a year. Snowfall averages 69.7 inches a year, most of it in January. That 53.9 inches is more than at 63 of the 65 Massachusetts stations used on this site (97%). West Roxbury, 2 miles north, has its own station (Jamaica Plain, MA): 49.4 inches a year, 4.5 less than here, and a July average high of 85°F against 82°F.

Sea level at the Boston tide gauge, 10 miles from Dedham, has risen 1.17 ± 0.03 inches per decade from 1921 to 2025, NOAA's linear trend; at that pace it is 11.7 inches in a hundred years. That is faster than at 68 of the 144 U.S. gauges with a NOAA trend.

Since 1996, the National Weather Service has logged 496 flood, rain, thunderstorm wind and lightning events that began within 10 miles of Dedham: 302 thunderstorm wind reports, 102 floods, 59 flash floods and 33 lightning strikes. They killed 0 people and injured 32, and the NWS estimated $79.7 million in property and crop damage. The strongest thunderstorm gust on record here was 75 mph, on July 7, 2021. July has had the most flash floods, 35 of 59. Of the 339 Massachusetts cities on this site with a flash flood on record, 328 have had fewer than Dedham.

Flood insurance policyholders in Dedham's ZIP code 02026 have filed 77 claims with the National Flood Insurance Program since 1978, and were paid $437,000 for buildings and contents, in the dollars of each year. The most came from Flooding in 1998: 27 claims (35% of all) and $143,000, then March 2010 Nor'easter in 2010 with 20. The year with the most claims was 2010, with 20. 77% 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, 153 have fewer than Dedham.