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Has the climate in Dorchester changed?

Dorchester has warmed about 2.6°F since 1971.

About 0.5°F per decade, measured from Dorchester's official daily weather records, 1971–2025. Individual years still bounce around — some recent ones came in cool — but the long-term line has clearly risen.

Is that a lot? Dorchester's warming is broadly in line with other cities in United States — neither unusually fast nor unusually slow.

What has actually changed

Each card compares the 1970s (the first ten years of the record) with recent years (the last ten) — the same span the headline and the chart use.

Freezing nights
15 fewer nights
1970s
128 / yr
Recent
113 / yr
Milder winters — fewer frosts
Average temperature
+2.1°F
1970s
50.3°F
Recent
52.4°F
A steady upward drift
Hot days above 90°F
1 fewer day
1970s
24 / yr
Recent
23 / yr
Slightly fewer hot days
Rainy days
10 more days
1970s
120 / yr
Recent
130 / yr
Wetter on average

Dorchester's temperature, year by year

Average temperature for each year from 1971 to 2025.

47°49°51°53°55°1971: 50.9°F1972: 49.1°F1973: 52.5°F1974: 50.3°F1975: 51.1°F1976: 49.8°F1977: 50.5°F1978: 49.1°F1979: 51.2°F1980: 49.4°F1981: 48.9°F1982: 48.9°F1983: 51.3°F1984: 51.0°F1985: 50.2°F1986: 50.1°F1987: 51.1°F1988: 50.6°F1989: 50.1°F1990: 51.9°F1991: 51.6°F1992: 48.8°F1993: 49.3°F1994: 50.3°F1995: 50.1°F1996: 50.0°F1997: 49.2°F1998: 52.6°F1999: 53.0°F2000: 50.0°F2001: 51.8°F2002: 51.9°F2009: 49.8°F2010: 52.6°F2011: 51.5°F2012: 53.2°F2013: 51.1°F2014: 50.3°F2015: 51.5°F2016: 53.3°F2017: 52.4°F2018: 52.1°F2019: 51.2°F2020: 53.6°F2021: 53.4°F2022: 53.0°F2023: 53.7°F2024: 53.6°F2025: 51.9°Flong-term trend1971198019902000201020202025
a warmer-than-average year a cooler-than-average year

Each bar is one year. Most recent years sit above the older ones. Some recent years still came in cool — warming is a slope, not a straight climb.

In day-to-day terms, that long-term shift shows up as about 17 fewer freezing nights a year and about 4 fewer days above 90°F compared with the 1970s.

When in the year the change shows up

How much warmer each month is now than in the 1970s. Useful if you garden or care about a particular season — otherwise the headline above already has the answer.

-0.5°0.0°+0.5°+1.0°+1.5°+2.0°January: +1.2°F+1.2JFebruary: +0.7°F+0.7FMarch: -0.5°F-0.5MApril: +0.8°F+0.8AMay: +0.3°F+0.3MJune: +0.4°F+0.4JJuly: +0.7°F+0.7JAugust: +0.9°F+0.9ASeptember: +1.4°F+1.4SOctober: +0.9°F+0.9ONovember: +0.6°F+0.6NDecember: +1.8°F+1.8D

December has warmed the most — about 1.8°F. The warming runs across the whole year, not just one season.

Methodology & sources

Temperature — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Jamaica Plain (NOAA GHCN station USC00193890), about 4 km from the city centre.

How we build these numbers →