Portland — Water Temperature in May

Water Temperature Range

14°C

minimum

16°C

average

18°C

maximum

Water Temperature Chart for May

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

	2026	2025	2024	2023
MAY 1	17°C	18°C	17°C	16°C
MAY 2	17°C	18°C	16°C	16°C
MAY 3	17°C	18°C	16°C	16°C
MAY 4	17°C	17°C	16°C	15°C
MAY 5	17°C	17°C	16°C	16°C
MAY 6	17°C	17°C	16°C	16°C
MAY 7	17°C	17°C	16°C	16°C
MAY 8	16°C	17°C	16°C	15°C
MAY 9	16°C	17°C	16°C	15°C
MAY 10	16°C	17°C	16°C	15°C
MAY 11	16°C	17°C	16°C	15°C
MAY 12	16°C	17°C	16°C	16°C
MAY 13	16°C	17°C	16°C	16°C
MAY 14	16°C	17°C	15°C	15°C
MAY 15	16°C	17°C	16°C	15°C
MAY 16	16°C	17°C	15°C	15°C
MAY 17	17°C	17°C	15°C	15°C
MAY 18	17°C	17°C	15°C	15°C
MAY 19	17°C	17°C	15°C	15°C
MAY 20	17°C	17°C	15°C	16°C
MAY 21	16°C	16°C	15°C	15°C
MAY 22	17°C	17°C	15°C	14°C
MAY 23	16°C	16°C	15°C	14°C
MAY 24	16°C	15°C	15°C	14°C
MAY 25	17°C	16°C	15°C	14°C
MAY 26	17°C	15°C	15°C	15°C
MAY 27	17°C	15°C	14°C	14°C
MAY 28	17°C	16°C	14°C	15°C
MAY 29	17°C	16°C	15°C	14°C
MAY 30	17°C	15°C	15°C	14°C
MAY 31	17°C	15°C	14°C	15°C

Climate and Swimming Opportunities in Portland in May

Average Day Air Temperature

17°C

Average Night Air Temperature

9°C

Precipitation Amount per Month

48 mm

Number of Rainy Days

Daylight per Day

10 hrs

Sunshine per Day

4 hrs

Average Wind Speed

17 km/h

Average Humidity

72%

At such water and air temperatures, swimming often feels chilly and is best for short swims. Getting out can feel cold, so it helps to have dry clothes ready right away.