Boston — Water Temperature in October

Water Temperature Range

9°C

minimum

15°C

average

19°C

maximum

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Water Temperature Chart for Month

The chart shows the average daily water temperature for each day of the month based on historical data.

Table of Water Temperatures by Day of the Month for Previous Years

Day	2025	2024	2023	2022
OCT 1	18°C	18°C	17°C	18°C
OCT 2	18°C	18°C	17°C	18°C
OCT 3	17°C	17°C	18°C	17°C
OCT 4	17°C	15°C	17°C	18°C
OCT 5	17°C	16°C	18°C	17°C
OCT 6	17°C	17°C	17°C	17°C
OCT 7	17°C	17°C	18°C	17°C
OCT 8	17°C	17°C	17°C	17°C
OCT 9	17°C	18°C	17°C	17°C
OCT 10	17°C	17°C	17°C	17°C
OCT 11	16°C	17°C	17°C	16°C
OCT 12	16°C	16°C	17°C	16°C
OCT 13	16°C	16°C	17°C	16°C
OCT 14	16°C	16°C	18°C	16°C
OCT 15	16°C	16°C	18°C	15°C
OCT 16	15°C	15°C	18°C	15°C
OCT 17	16°C	15°C	18°C	16°C
OCT 18	15°C	14°C	17°C	15°C
OCT 19	15°C	15°C	17°C	15°C
OCT 20	14°C	14°C	17°C	14°C
OCT 21	14°C	14°C	16°C	14°C
OCT 22	14°C	13°C	16°C	14°C
OCT 23	14°C	13°C	17°C	14°C
OCT 24	14°C	14°C	16°C	14°C
OCT 25	14°C	14°C	15°C	15°C
OCT 26	14°C	13°C	16°C	15°C
OCT 27	14°C	14°C	15°C	15°C
OCT 28	13°C	13°C	14°C	15°C
OCT 29	13°C	13°C	15°C	15°C
OCT 30	13°C	13°C	14°C	14°C
OCT 31	12°C	12°C	14°C	14°C

October: Climate and Swimming Opportunities

Average Night Air Temperature

6°C

Average Day Air Temperature

17°C

Precipitation Amount per Month

105 mm

Number of Rainy Days

Daylight per Day

11 hrs

Sunshine per Day

6 hrs

Average Wind Speed

16 km/h

Average Humidity

70%

With such a ratio between the average monthly temperatures of water and air, swimming feels very cold and is only for cold-water enthusiasts. Most people will prefer just a brief splash, because warming up afterward can take time.