Historical weather data, all-time temperature records, and monthly climate averages for South Boston, MA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5th in South Boston sits in classic early-spring limbo — the average high of 53° sounds promising, but 90 years of data show this date can swing wildly, from a balmy 75° back in 1991 to a brutal 20° low in 1995. There's a 38% chance of rain today, with a lingering 6% shot at snow that the calendar would rather you forget.
South Boston's weather has real range — the thermometer has climbed to 103° (July 2011) and crashed to -14° (February 1943), a 117-degree spread that earns some respect. The wettest single day on record dumped 7.06 inches in August 1955, and a January 2022 storm buried the city under 23.6 inches of snow in one shot.
Summer is the sweet spot, with highs peaking around 82–83° in mid-to-late July — the best window for outdoor plans. January and February are the grind, with average highs barely clearing the mid-to-upper 30s. If you're trying to dodge rain, avoid mid-March, when weekly precipitation averages top out at 1.1 inches.