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Weather & Climate in Chatham, MA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Chatham experiences four distinct seasons with an average annual temperature of 50°F (10°C). Winters average 32°F in January while summers reach 70°F in July. The area gets 275 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 45.9 inches (wetter than the 38-inch national average). The area receives 24.5 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 37. The city sits at an elevation of 35 feet.
Temperature
32°F Jan (-0°C)
70°F Jul (21°C)
| Annual Average | 50.3°F |
| 7% below US avg | |
| January Average | 32°F (-0°C) |
| July Average | 70°F (21°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 35 ft (11 m) |
| Area | 2.6 sq mi (6.8 km²) |
| Population Density | 611/sq mi |
| Coordinates | 41.6739°N, 69.9630°W |
| Timezone | America/New_York |
| County | Barnstable County County |
| Nearest Airport | New Bedford Regional (EWB) 51 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 37.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 89.1 / 100 |
| Social Vulnerability | 34.5 / 100 |
| Community Resilience | 99.3 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Relatively High |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively Moderate |
| Hail | Relatively Low |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively High |
| Ice Storm | Relatively Low |
| Drought | Relatively Low |
| Cold Wave | Relatively Low |
| Landslide | Relatively Low |
| Coastal Flood | Very High |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
7 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.1.
| Mar 22, 1996 | 2 km NE of Bristol, Rhode Island | M3.1 | 106 km | 12 km |
| Mar 12, 2002 | 52 km E of Chatham, Massachusetts | M3.0 | 53 km | 1 km |
| Jul 22, 2003 | 72 km NNE of Provincetown, Massachusetts | M3.0 | 106 km | 10 km |
| Jan 8, 1998 | 52 km ENE of Rockport, Massachusetts | M2.9 | 132 km | 25 km |
| Oct 11, 1990 | 5 km NNE of The Pinehills, Massachusetts | M2.7 | 58 km | 13 km |
| Apr 22, 1996 | 3 km NE of North Westport, Massachusetts | M2.6 | 91 km | 5 km |
| Jun 7, 2002 | 3 km NNW of Hopedale, Massachusetts | M2.5 | 143 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Hurricane History
8 hurricanes (Category 1+) recorded within 500 km since 1980. Strongest on record: Category 2.
| Year | Name | Category | Max Wind | Closest |
| 2021 | Henri | Category 1 | 75 mph | 268 km |
| 2019 | Dorian | Category 2 | 98 mph | 271 km |
| 2014 | Arthur | Category 1 | 75 mph | 165 km |
| 2009 | Bill | Category 1 | 86 mph | 284 km |
| 2008 | Kyle | Category 1 | 86 mph | 251 km |
| 1996 | Edouard | Category 1 | 81 mph | 187 km |
| 1991 | Bob | Category 2 | 104 mph | 112 km |
| 1985 | Gloria | Category 1 | 86 mph | 237 km |
Source: NOAA IBTrACS (Category 1+, 1980–2026).
Tornado History
25 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 1 fatality, 4 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Aug 28, 1970 | EF2 | 78 km | 1.0 mi | 0 |
| Nov 18, 1967 | EF2 | 84 km | 0.1 mi | 0 |
| Dec 18, 1951 | EF2 | 58 km | 0.1 mi | 0 |
| Aug 18, 2023 | EF1 | 99 km | 0.4 mi | 0 |
| Aug 8, 2023 | EF1 | 74 km | 0.9 mi | 0 |
| Jul 23, 2019 | EF1 | 27 km | 5.5 mi | 0 |
| Jul 23, 2019 | EF1 | 24 km | 0.3 mi | 0 |
| Jul 23, 2019 | EF1 | 10 km | 2.8 mi | 0 |
| Jul 10, 1989 | EF1 | 99 km | 0.1 mi | 0 |
| Sep 16, 1986 | EF1 | 86 km | 0.1 mi | 0 |
| Aug 22, 1977 | EF1 | 26 km | 0.1 mi | 0 |
| Aug 9, 1968 | EF1 | 78 km | 1.0 mi | 0 |
| Aug 9, 1968 | EF1 | 37 km | 0.1 mi | 0 |
| Jul 4, 1964 | EF1 | 83 km | 2.3 mi | 0 |
| Aug 8, 2023 | EF0 | 36 km | 1.2 mi | 0 |
| Sep 1, 2021 | EF0 | 22 km | 0.1 mi | 0 |
| Oct 29, 2018 | EF0 | 60 km | 0.1 mi | 0 |
| Jul 24, 2012 | EF0 | 58 km | 0.0 mi | 0 |
| Aug 20, 1997 | EF0 | 68 km | 0.1 mi | 0 |
| Aug 6, 1997 | EF0 | 94 km | 0.1 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
1 wildfire (100+ acres) recorded within 100 km. Largest: NOMANS AERIAL RX (546 acres, 2008).
| Year | Name | Acres Burned | Distance |
| 2008 | NOMANS AERIAL RX | 546 | 85 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 32°F (-0°C) | 3.7 in | Coldest |
| February | 32°F (-0°C) | 3.7 in | |
| March | 38°F (3°C) | 3.8 in | |
| April | 45°F (7°C) | 3.6 in | |
| May | 54°F (12°C) | 3.5 in | |
| June | 63°F (17°C) | 3.1 in | |
| July | 70°F (21°C) | 3.0 in | Warmest, Driest |
| August | 69°F (20°C) | 3.2 in | |
| September | 63°F (17°C) | 3.6 in | |
| October | 53°F (12°C) | 3.9 in | |
| November | 45°F (7°C) | 4.3 in | |
| December | 37°F (3°C) | 4.3 in | Wettest |
Chatham has a seasonal temperature swing of 38°F / from 32°F in January to 70°F in July. Total annual precipitation is 43.5 inches, with December being the wettest month (4.3") and July the driest (3.0").