Portsmouth — Water Temperature in May

Water Temperature Range

13°C

minimum

18°C

average

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

May: Climate and Swimming Opportunities

Average Night Air Temperature

14°C

Average Day Air Temperature

22°C

Precipitation Amount per Month

90 mm

Number of Rainy Days

Daylight per Day

14 hrs

Sunshine per Day

9 hrs

Average Wind Speed

15 km/h

Average Humidity

71%

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.