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Boston in August: weather, sea & travel advice

This month's data profile

Rain shapes the decision

Boston in August is climatically well suited to city breaks, beach holidays and family holidays. The average daily high is around 27 °C, and the sea is about 19 °C. With about 12 rainy days it is wet.

Historical monthly averages, not a weather forecast. Individual days and years can differ substantially.

Rank among 12 monthly averages

70/100 · #2

Warmth

Dryness

Sun

Sea warmth

Published best categories: Overall, Beach, City break, Family

Boston · AugustPhoto: Chris Wood ( User:chris_j_wood ) · CC BY-SA 4.0

Average high: 27 °C
Average low: 17 °C
Sea: 19 °C
Rainy days (est.): 12 rainy days (est.)
Sun (est.): 7 h/day
Humidity: 73 %

Climate evidence with direct month comparison

The highlighted row is the selected month. Precipitation total and rainy days are separate monthly averages.

Climate averages for Boston: selected and adjacent months
Month	Avg high °C	Avg low °C	Rainy days (est.)	Precipitation mm	Sun h/day (est.)	Humidity %	Wind m/s	Sea °C	Score
July	28	17	13	98	7.3	75	0.3	18	67
August (selected)	27	17	12	92	6.6	73	0.4	19	70
September	23	13	10	104	5.2	75	0.5	17	72

How do the previous and next months compare?

Baseline: August (70/100)

Positive and negative values show the change from the selected month.

	Score Δ	Average high Δ	Average low Δ	Rainy days Δ	Rain Δ	Sun Δ	Humidity Δ	Wind Δ	Sea Δ
July	-3	+0.2 °C	+0.6 °C	+1.3	+6 mm	+0.7 h	+1.7 %	-0.1 m/s	-0.6 °C
September	+2	-3.9 °C	-3.9 °C	-1.6	+11.3 mm	-1.4 h	+2 %	+0.1 m/s	-1.6 °C

All twelve months in context

JanUnsuitable27 FebUnsuitable30 MarUnsuitable30 AprUnsuitable40 MayLimited54 JunGood65 JulGood67 AugGood70 SepGood72 OctLimited49 NovUnsuitable33 DecUnsuitable25

Rainy days (estimated)

Sunshine hours (estimated)h/day

Average daily high°C

Sea temperature°C

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Useful next decisions

Boston · Month by month

Seattle · August Nagano · August Montenegro · August Vancouver · August

Frequently asked questions

How warm is Boston in August?

The average daily high is around 27 °C, with an average daily low of about 17 °C.

Can you swim in Boston in August?

The sea is about 19 °C (refreshing).

Does it rain a lot in Boston in August?

The curated estimate is about 12 rainy days per month, not a directly measured long-term average. Total precipitation averages around 92 mm for the month. A rainy day does not mean all-day rain.

When is the best time to visit Boston?

By the climate score, June, July, August and September are the strongest months for Boston. For a beach trip: July, August and September. August is one of them.