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East Boston, Massachusetts climate

Cfa Humid subtropical

East Boston has a seasonal cool-temperate climate (Humid subtropical, Köppen Cfa). The hottest month is July with an average daily high near 82°F, while the coldest is January averaging around 23°F at night. Precipitation is fairly even year-round, totalling about 44 inches. Winters bring significant snowfall (49 inches of snow per year on average).

☀️ Summers

Warm

Highs near 82°F in July.

About 14 days a year above 90 °F

❄️ Winters

Cold

Lows near 23°F in January.

About 92 freezing nights a year

🌧️ Rain & snow

Wet

About 44 in of rain a year, plus 49 in of snow.

Snow falls through the winter months

⛅ Sky & trend

Partly cloudy

A roughly even mix of sun and cloud.

+0.3 °F vs 50 years ago

Temperature & precipitation

Daily high–low temperature range with the monthly average, plus monthly precipitation split into rain and snow · 1991–2020 normals · hover a month for the exact figures

Clear vs cloudy days

Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day counts

East Boston climate normals (1991–2020)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°F)	37	39	46	56	67	76	82	80	73	62	52	42
Avg temp (°F)	30	32	38	49	58	68	74	73	66	55	45	36
Avg low (°F)	23	25	31	41	50	60	66	65	58	48	38	29
Precipitation (in)	3.4	3.2	4.2	3.6	3.3	3.9	3.3	3.2	3.6	4.0	3.7	4.3
Snowfall (in)	14.3	14.4	9.0	1.6	—	—	—	—	—	0.2	0.7	9.0

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Avg high (°F)	37	39	46	56	67	76
Avg temp (°F)	30	32	38	49	58	68
Avg low (°F)	23	25	31	41	50	60
Precipitation (in)	3.4	3.2	4.2	3.6	3.3	3.9
Snowfall (in)	14.3	14.4	9.0	1.6	—	—

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°F)	82	80	73	62	52	42
Avg temp (°F)	74	73	66	55	45	36
Avg low (°F)	66	65	58	48	38	29
Precipitation (in)	3.3	3.2	3.6	4.0	3.7	4.3
Snowfall (in)	—	—	—	0.2	0.7	9.0

How often — frequency of weather events

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	12	11	12	12	12	11	9	9	9	10	10	12
Days with high ≥ 90°F (days)	—	—	—	0.1	0.6	3	6	4	0.8	—	—	—
Days with low ≤ 32°F (days)	25	22	16	2	—	—	—	—	—	0.2	7	20
Days with snowfall ≥ 1 in (days)	4	3	2	0.3	—	—	—	—	—	0.1	0.2	2

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Days with measurable rain (days)	12	11	12	12	12	11
Days with high ≥ 90°F (days)	—	—	—	0.1	0.6	3
Days with low ≤ 32°F (days)	25	22	16	2	—	—
Days with snowfall ≥ 1 in (days)	4	3	2	0.3	—	—

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	9	9	9	10	10	12
Days with high ≥ 90°F (days)	6	4	0.8	—	—	—
Days with low ≤ 32°F (days)	—	—	—	0.2	7	20
Days with snowfall ≥ 1 in (days)	—	—	—	0.1	0.2	2

Sky & atmosphere

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	63	62	62	64	65	63	57	56	55	60	62	63
Clear days (≤ 30% cloud)	5	5	6	5	5	5	6	7	9	7	6	5
Partly cloudy days (30–70%)	11	11	10	10	10	11	14	12	10	10	10	12
Cloudy days (≥ 70%)	14	13	14	15	16	14	11	12	11	14	14	14
Relative humidity (%)	88	87	83	80	79	79	74	73	74	78	82	86
Wind speed (mph)	2.3	2.6	2.3	1.4	1.0	0.9	0.8	0.9	1.1	1.4	1.5	1.7

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Cloud cover (%)	63	62	62	64	65	63
Clear days (≤ 30% cloud)	5	5	6	5	5	5
Partly cloudy days (30–70%)	11	11	10	10	10	11
Cloudy days (≥ 70%)	14	13	14	15	16	14
Relative humidity (%)	88	87	83	80	79	79
Wind speed (mph)	2.3	2.6	2.3	1.4	1.0	0.9

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	57	56	55	60	62	63
Clear days (≤ 30% cloud)	6	7	9	7	6	5
Partly cloudy days (30–70%)	14	12	10	10	10	12
Cloudy days (≥ 70%)	11	12	11	14	14	14
Relative humidity (%)	74	73	74	78	82	86
Wind speed (mph)	0.8	0.9	1.1	1.4	1.5	1.7

30-year delta table (1991–2020 minus 1981–2010, °F)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Δ Max temp	+1.0	+0.3	+0.1	+0.8	+0.5	+0.3	+0.7	+0.8	+0.7	+0.7	+0.1	+1.0
Δ Avg temp	+0.9	+0.1	+0.0	+0.5	+0.5	+0.3	+0.7	+0.6	+0.7	+0.8	+0.0	+1.0
Δ Min temp	+0.9	-0.1	+0.0	+0.2	+0.4	+0.2	+0.6	+0.5	+0.8	+1.0	-0.1	+1.0

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Δ Max temp	+1.0	+0.3	+0.1	+0.8	+0.5	+0.3
Δ Avg temp	+0.9	+0.1	+0.0	+0.5	+0.5	+0.3
Δ Min temp	+0.9	-0.1	+0.0	+0.2	+0.4	+0.2

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Δ Max temp	+0.7	+0.8	+0.7	+0.7	+0.1	+1.0
Δ Avg temp	+0.7	+0.6	+0.7	+0.8	+0.0	+1.0
Δ Min temp	+0.6	+0.5	+0.8	+1.0	-0.1	+1.0

Methodology & sources

Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Boston (NOAA GHCN station USW00014739), about 3 km from the city centre.

Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.

How we build these numbers →