Seattle weather in August: Seattle, Washington: normal highs, lows, rain and records for August
Seattle in August has a normal high of 78°F and a normal low of 57°F, a daily mean of 67°F, falling from 79°F on the 1st to 76°F by the 31st. Measurable precipitation falls on 5 days in a normal August, 0.97 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 25°C and low of 14°C, 25 mm of precipitation in August.
- NOAA stationSeattle Tacoma International Airport
- Station IDUSW00024233
- Location47.44°N 122.31°W
- Elevation370 ft (113 m)
- From the center12 miles
- Population780,995
- Jan 48° 38°
- Feb 50° 38°
- Mar 54° 40°
- Apr 59° 43°
- May 66° 49°
- Jun 71° 53°
- Jul 77° 57°
- Aug 78° 57°
- Sep 72° 54°
- Oct 61° 47°
- Nov 52° 41°
- Dec 47° 37°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Seattle in August?
The normal high is 78°F and the normal low 57°F, for a daily mean of 67.4°F. August is 0.3°F warmer than July and 4.8°F warmer than September. August is the warmest month of the year in Seattle and the 11th wettest. Across the month the normal high falls 3°F, from 79°F on August 1 to 76°F on August 31. From one year to the next August's mean temperature typically moves about 1.4°F either way (NOAA's standard deviation), so roughly two Augusts in three average between 66°F and 69°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 21%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| August 1 | 79°F | 58°F | 14% | 6% |
| August 8 | 79°F | 58°F | 14% | 6% |
| August 15 | 78°F | 57°F | 15% | 7% |
| August 22 | 77°F | 57°F | 18% | 8% |
| August 31 | 76°F | 56°F | 21% | 10% |
Every day of August: normal high, low and chance of precipitation (warmest afternoon August 1, coldest night August 31)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| August 1 | 79°F | 58°F | 14% | 6% | 15 h |
| August 2 | 79°F | 58°F | 14% | 6% | 15 h |
| August 3 | 79°F | 58°F | 14% | 6% | 14 h 50 min |
| August 4 | 79°F | 58°F | 14% | 6% | 14 h 50 min |
| August 5 | 79°F | 58°F | 14% | 6% | 14 h 50 min |
| August 6 | 79°F | 58°F | 14% | 6% | 14 h 50 min |
| August 7 | 79°F | 58°F | 14% | 6% | 14 h 40 min |
| August 8 | 79°F | 58°F | 14% | 6% | 14 h 40 min |
| August 9 | 79°F | 58°F | 14% | 7% | 14 h 40 min |
| August 10 | 78°F | 58°F | 14% | 7% | 14 h 30 min |
| August 11 | 78°F | 58°F | 15% | 7% | 14 h 30 min |
| August 12 | 78°F | 58°F | 15% | 7% | 14 h 30 min |
| August 13 | 78°F | 58°F | 15% | 7% | 14 h 30 min |
| August 14 | 78°F | 58°F | 15% | 7% | 14 h 20 min |
| August 15 | 78°F | 57°F | 15% | 7% | 14 h 20 min |
| August 16 | 78°F | 57°F | 15% | 7% | 14 h 20 min |
| August 17 | 78°F | 57°F | 16% | 8% | 14 h 10 min |
| August 18 | 78°F | 57°F | 16% | 8% | 14 h 10 min |
| August 19 | 77°F | 57°F | 16% | 8% | 14 h 10 min |
| August 20 | 77°F | 57°F | 17% | 8% | 14 h |
| August 21 | 77°F | 57°F | 17% | 8% | 14 h |
| August 22 | 77°F | 57°F | 18% | 8% | 14 h |
| August 23 | 77°F | 57°F | 18% | 9% | 13 h 50 min |
| August 24 | 77°F | 57°F | 18% | 9% | 13 h 50 min |
| August 25 | 77°F | 57°F | 19% | 9% | 13 h 50 min |
| August 26 | 76°F | 57°F | 19% | 9% | 13 h 50 min |
| August 27 | 76°F | 56°F | 20% | 10% | 13 h 40 min |
| August 28 | 76°F | 56°F | 20% | 10% | 13 h 40 min |
| August 29 | 76°F | 56°F | 21% | 10% | 13 h 40 min |
| August 30 | 76°F | 56°F | 21% | 10% | 13 h 30 min |
| August 31 | 76°F | 56°F | 21% | 10% | 13 h 30 min |
- Normal high
- 78°FAugust average
- Normal low
- 57°FAugust average
- Precipitation
- 0.97 inmonth total
- Days with precipitation
- 50.01 inch or more
- Days at 90°F or more
- 1
- Daylight
- 15 h to 13 h 30 minAugust 1 to August 31
- Days at 70°F or more
- 27
- Days at 80°F or more
- 10
- Sunshine
- 78%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024233; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Seattle in August?
On a given August day the chance of 0.01 inch or more is 16% on average, highest around August 31 (21%). In all, 0.97 in falls on 5 days of a normal August.
In a normal August in Seattle, 1 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00024233.
How humid and windy is Seattle in August?
At 3 p.m. the normal temperature is 73°F with 47% relative humidity and a dew point of 51°F; at 6 a.m. it is 57°F with 85% humidity. The wind averages 6.8 mph, most often from the west in the afternoon.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 57°F | 52°F | 85% | 5.1 mph | 29% |
| 9 a.m. | 62°F | 53°F | 72% | 6.6 mph | 32% |
| noon | 69°F | 53°F | 57% | 8.0 mph | 37% |
| 3 p.m. | 73°F | 51°F | 47% | 8.6 mph | 35% |
| 6 p.m. | 70°F | 51°F | 51% | 7.4 mph | 38% |
| 9 p.m. | 64°F | 52°F | 65% | 7.2 mph | 49% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024233. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for August in Seattle?
The warmest August temperature on this station's record (since 1945) is 99°F, on August 9, 1960; the coldest is 44°F, on August 21, 1947. The wettest August brought 4.59 in (1975).
The August mean against the 1991-2020 normal of 67.4°F: 2021 67.5°F (+0.1), 2022 70.0°F (+2.6), 2023 69.9°F (+2.5), 2024 66.5°F (−0.9), 2025 68.8°F (+1.4), 2026 67.7°F (+0.3). 5 of 6 ran warmer than normal.
| August | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 67.5°F | +0.1°F | 0.11 in |
| 2022 | 70.0°F | +2.6°F | 0.05 in |
| 2023 | 69.9°F | +2.5°F | 0.27 in |
| 2024 | 66.5°F | −0.9°F | 1.66 in |
| 2025 | 68.8°F | +1.4°F | 1.14 in |
| 2026 | 67.7°F | +0.3°F | 0.56 in |
Source: records: ACIS, station USW00024233; recent months: ACIS, station USW00024233. Records and recent months use complete months only.
How does August in Seattle compare across Washington?
Across the 96 places PlainClimate covers in Washington, August normal highs run from 67°F in Long Beach to 91°F in Pasco; Seattle's is 78°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.