# Seattle in August: weather

Seattle, United States (North America). Ten-year climatology (2015-2024), not a forecast. Page: https://beaufixe.net/en/weather/seattle/august

## Key figures

| Indicator | Value |
|---|---|
| Afternoon (mean daily max) | 24.8 °C |
| Night (mean daily min) | 15 °C |
| Sea (surface) | 11.7 °C |
| Rainy days (≥ 1 mm) | 5 / month |
| Relative humidity | 68 % |
| Probability of a 25 °C+ afternoon | 47 % |

## Month by month

| Month | Afternoon | Night | Sea | Rain (d) |
|---|---|---|---|---|
| January | 8.1 °C | 2.7 °C | 8.3 °C | 18 |
| February | 8.3 °C | 2.5 °C | 8.3 °C | 15 |
| March | 11 °C | 3.7 °C | 8.4 °C | 15 |
| April | 13.8 °C | 5.8 °C | 9.1 °C | 14 |
| May | 17.9 °C | 9.4 °C | 10 °C | 10 |
| June | 21.1 °C | 12.2 °C | 10.6 °C | 8 |
| July | 24.6 °C | 14.6 °C | 11.2 °C | 4 |
| August | 24.8 °C | 15 °C | 11.7 °C | 5 |
| September | 20.5 °C | 12.7 °C | 11.3 °C | 10 |
| October | 15.1 °C | 8.9 °C | 10.3 °C | 14 |
| November | 10.3 °C | 5.3 °C | 9.7 °C | 18 |
| December | 7.4 °C | 3 °C | 8.8 °C | 19 |

Best months : August, July, June.

## Before you go

- **Safety** : No specific restrictions. Usual precautions apply. (official advice updated 18 August 2026 — https://www.gov.uk/foreign-travel-advice/usa)
- **Entry** (British passport) : No visa, but an electronic travel authorisation (ESTA) must be obtained online before departure. Passport valid until your return date. Apply for ESTA on the official website or app; not available if you visited Cuba since 2021 or Iran, Iraq, Libya, North Korea, Somalia, Sudan, Syria or Yemen. (per the UK Foreign Office, 18 August 2026)
- **Vaccines** : Routine vaccines up to date (measles in particular).
- **Yellow fever** : No yellow fever locally, vaccine not recommended. No entry requirement.
- **Malaria** : None.
  (per the CDC, page reviewed 26 June 2024 — https://wwwnc.cdc.gov/travel/destinations/traveler/none/united-states)

## Sources

Air, rain, humidity: ERA5-Land reanalysis (Copernicus) served by Open-Meteo (CC BY 4.0). Sea: NOAA OISST. Safety: FCDO (OGL v3), zones reviewed by Beau Fixe. Entry: France Diplomatie (Licence Ouverte 2.0) / FCDO. Health: CDC (public domain). Details: https://beaufixe.net/en/legal#sources

Beau Fixe — https://beaufixe.net — not a forecast; only the authorities are authoritative for safety, entry rules and health.