Seattle, WA weather in August
Seattle is mild and mostly dry in August: highs average 77°F and nights drop to about 57°F. Rain falls on about 6 days. This is the peak of the warm season in Seattle. A great month for outdoor plans.
- Normal high
- 77°F
- Normal low
- 57°F
- Wet days
- 6
- 1.0 in total
- Muggy days
- 0
- dew point 65°F+
How August changes from start to finish
| August 1 | August 31 | |
|---|---|---|
| Normal high | 78°F | 75°F |
| Normal low | 58°F | 56°F |
| Chance of a wet day | 15% | 23% |
| Sunrise / sunset | 5:47 am / 8:44 pm | 6:26 am / 7:52 pm |
| Daylight | 14.9 h | 13.4 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Pacific Time).
A typical August day
- 6 am60°Fdew point 54°F
- 9 am65°Fdew point 54°F
- Noon71°Fdew point 54°F
- 3 pm76°Fdew point 53°F
- 6 pm74°Fdew point 53°F
- 9 pm67°Fdew point 53°F
NOAA hourly normals (local standard time) from Seattle Boeing Fld (5 mi away); average wind 5 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F22 of 31
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph10 of 31
- Hot dayshigh 90°F or more1 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow6 of 31
- Notable rainat least 0.10 in3 of 31
- Freezing nightslow 32°F or below0 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per August, counted from daily records for each year 1991-2020.
Rain in August
Normal precipitation is 1.0 in; a dry August brings about 0.3 in and a wet one about 1.4 in (25th and 75th percentiles). About 1 day brings half an inch or more.
How August varies from year to year
- Warmest August, 1991-20202017: average high 81°F
- Coolest August1995: average high 71°F
- Wettest August2004: 3.0 in
- Driest August2012: no measurable precipitation
- Highest reading97°F (August 16, 2020)
- Lowest reading47°F (August 17, 2000)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
August compared with July and September
| July | August | September | |
|---|---|---|---|
| Normal high | 77°F | 77°F | 71°F |
| Normal low | 57°F | 57°F | 53°F |
| Wet days | 5 | 6 | 9 |
| Comfortable days | 22 | 22 | 23 |
| Daylight | 15.5 h | 14.2 h | 12.6 h |
Highs change by 0°F from July and -6°F into September.
Nearby alternatives in August
- Warmer: Leavenworth, WA78 mi · high 87°F · 2 wet days
- Drier: Leavenworth, WA78 mi · high 87°F · 2 wet days
- Cooler: Port Angeles, WA62 mi · high 70°F · 6 wet days
How Seattle ranks in August
- Normal high343rd warmest of 378 cities; 5th of 9 in Washington
- Wet days111th driest of 378
- Comfortable days14th most of 341
What to pack for Seattle in August
- A swimsuit – about 10 beach days
- Sunglasses and sunscreen – about 14.2 hours of daylight and highs near 77°F
Heating and cooling
August has 23 heating degree days and 86 cooling degree days (base 65°F), 2% of the year's total heating and cooling demand.
Questions
How hot is Seattle in August?
The normal high is 77°F and the normal low is 57°F. From 1991 to 2020 the hottest August reading was 97°F (August 16, 2020).
Does it rain a lot in Seattle in August?
About 6 days in August have at least 0.01 in of precipitation, and the normal total is 1.0 in. The wettest August in 1991-2020 was in 2004 (3.1 in); the driest was in 2012, with no measurable precipitation.
Is August a good time to visit Seattle?
August ranks 3rd of 12 months on our comfort score for Seattle (83 out of 100). It has about 22 comfortable days and about 1 day at 90°F or hotter. The best months are June, July and August.
Where the numbers come from
- Temperature, rain, snowfall, snow depth and frost dates: Seattle Sand Pt WSFO (USW00094290), 6.6 mi NNE of the city center, 60 ft (113 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour: Seattle Boeing Fld (USW00024234), 5.4 mi SSE of the city center, 20 ft (153 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Seattle-Tacoma International Airport (727930-24233), 11 mi S of the city center, 369 ft (196 ft higher than the city). Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).