Seattle — Water Temperature in August

Water Temperature Range

10°C

minimum

13°C

average

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

August: Climate and Swimming Opportunities

Average Night Air Temperature

13°C

Average Day Air Temperature

25°C

Precipitation Amount per Month

25 mm

Number of Rainy Days

Daylight per Day

14 hrs

Sunshine per Day

9 hrs

Average Wind Speed

11 km/h

Average Humidity

69%

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.