South Boston, Massachusetts, United States climate

Average temperatures, precipitation and all-time records for South Boston, Massachusetts, United States, with every day graded against ~45 years of local climate history (1981–2026). Its warmest month is July, averaging a high of 82°F, and its coldest is January, with an average low of 17°F.

South Boston is a densely populated neighborhood of Boston, Massachusetts, United States, located south and east of the Fort Point Channel and abutting Dorchester Bay. It has undergone several demographic transformations since being annexed to the city of Boston in 1804. via Wikipedia

How today compares

Latest recorded day: 2026-07-21. Each reading placed on South Boston, Massachusetts, United States's own ±7-day seasonal distribution.

High 82°F Normal · 47th pct

Low 62°F Normal · 41st pct

Feels-like 80°F Below Normal · 38th pct

Humidity 14.8 g/m³ Normal · 45th pct

Wind 16 mph Near Record · 99th pct

Precip 0.29 in Heavy · 83rd pct

Open South Boston in the live weather grader →

South Boston average temperatures by month

Typical daily high and low, and average precipitation, for each month in South Boston, Massachusetts, United States, based on 1981–2026 records. The wettest month is January (0.10 in on an average day).

Month	Avg high	Avg low	Avg precip
January	32°F	17°F	0.10 in
February	35°F	19°F	0.10 in
March	43°F	26°F	0.10 in
April	55°F	36°F	0.10 in
May	65°F	45°F	0.10 in
June	74°F	56°F	0.10 in
July	82°F	63°F	0.10 in
August	81°F	62°F	0.10 in
September	74°F	54°F	0.10 in
October	62°F	44°F	0.10 in
November	49°F	34°F	0.10 in
December	37°F	24°F	0.10 in

Jan 2°–44°

Feb 7°–47°

Mar 16°–55°

Apr 28°–66°

May 38°–75°

Jun 49°–83°

Jul 57°–89°

Aug 55°–89°

Sep 46°–83°

Oct 35°–71°

Nov 25°–61°

Dec 13°–49°

Each bar spans the 10th-percentile daily low to the 90th-percentile daily high (the range most days fall within), coloured cold → hot on a shared -10°F to 115°F scale, so the whole year's rhythm reads at a glance.

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Record extremes

Hottest day on record: 100°F on 2002-08-14
Coldest day on record: -15°F on 2015-02-24

All South Boston weather records →

Percentiles compare each day to South Boston, Massachusetts, United States's own history, so grades are relative to this location: a “Near Record” day here isn't the same temperature as elsewhere. How the grades work →