Chatham weather by month
What a typical year looks like in Chatham, Massachusetts: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Chatham Municipal Airport, 3 km from Chatham; records cover 1996–2026.
The year at a glance
- Precipitation a year
- 45.2 in1148 mm
- Snow a year
- Rare
- Last spring freeze
- Apr 11
- First fall freeze
- Nov 6
- Heating degree days
- 5,621
- Cooling degree days
- 512
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 11°−12° (heating, 99%) and 87°31° (cooling, 1%).
Month by month
Chatham in January
Highs average 39°4° and lows 26°−4°, with 3.8 in95 mm of precipitation in a typical January.
- Record high
- 59°15° (1998)
- Record low
- −5°−21° (2004)
- Heating degree days
- 1021
- Cooling degree days
- 0
Chatham in February
Highs average 40°4° and lows 26°−3°, with 3.6 in92 mm of precipitation in a typical February.
- Record high
- 63°17° (2023)
- Record low
- −4°−20° (2016)
- Heating degree days
- 904
- Cooling degree days
- 0
Chatham in March
Highs average 44°7° and lows 31°0°, with 4.4 in113 mm of precipitation in a typical March.
- Record high
- 66°19° (2012)
- Record low
- 8°−13° (2015)
- Heating degree days
- 851
- Cooling degree days
- 0
Chatham in April
Highs average 52°11° and lows 39°4°, with 4 in102 mm of precipitation in a typical April.
- Record high
- 85°29° (2002)
- Record low
- 23°−5° (2016)
- Heating degree days
- 581
- Cooling degree days
- 0
Chatham in May
Highs average 62°17° and lows 48°9°, with 3.3 in85 mm of precipitation in a typical May.
- Record high
- 90°32° (2007)
- Record low
- 31°−1° (2001)
- Heating degree days
- 314
- Cooling degree days
- 3
Chatham in June
Highs average 72°22° and lows 57°14°, with 3 in75 mm of precipitation in a typical June.
- Record high
- 93°34° (2012)
- Record low
- 41°5° (2026)
- Heating degree days
- 80
- Cooling degree days
- 61
Chatham in July
Highs average 79°26° and lows 64°18°, with 2.8 in71 mm of precipitation in a typical July.
- Record high
- 99°37° (1999)
- Record low
- 50°10° (2000)
- Heating degree days
- 6
- Cooling degree days
- 205
Chatham in August
Highs average 78°25° and lows 64°18°, with 3 in77 mm of precipitation in a typical August.
- Record high
- 98°37° (2006)
- Record low
- 49°9° (2004)
- Heating degree days
- 7
- Cooling degree days
- 181
Chatham in September
Highs average 71°22° and lows 58°14°, with 3.6 in91 mm of precipitation in a typical September.
- Record high
- 90°32° (2010)
- Record low
- 37°3° (2019)
- Heating degree days
- 79
- Cooling degree days
- 58
Chatham in OctoberThis month
Highs average 61°16° and lows 47°9°, with 4.2 in107 mm of precipitation in a typical October.
- Record high
- 83°28° (2011)
- Record low
- 28°−2° (1997)
- Heating degree days
- 335
- Cooling degree days
- 4
Chatham in November
Highs average 52°11° and lows 39°4°, with 4.5 in114 mm of precipitation in a typical November.
- Record high
- 73°23° (2024)
- Record low
- 16°−9° (2000)
- Heating degree days
- 586
- Cooling degree days
- 0
Chatham in December
Highs average 44°7° and lows 31°−1°, with 5 in127 mm of precipitation in a typical December.
- Record high
- 65°18° (2001)
- Record low
- 7°−14° (2017)
- Heating degree days
- 857
- Cooling degree days
- 0