Charlestown — Water Temperature in May

Water Temperature Range

8°C

minimum

16°C

average

21°C

maximum

Get instant access to real-time water temperatures for this and all other locations with our iOS and Android apps.

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

May: Climate and Swimming Opportunities

Average Night Air Temperature

11°C

Average Day Air Temperature

22°C

Precipitation Amount per Month

105 mm

Number of Rainy Days

Daylight per Day

14 hrs

Sunshine per Day

8 hrs

Average Wind Speed

11 km/h

Average Humidity

66%

At such water and air temperatures, swimming feels cool and invigorating. It’s comfortable for a quick dip, and you’ll feel fine as long as you warm up soon after.