ClimateForecastNovemberDecember >>

SeaTac (WA) Climate by Month

The temperature in SeaTac can vary quite a bit throughout the year. Temperatures can be warm during the warmest months, and cold during the cooler months. It is also known for its large amounts of rain/snowfall. Let’s explore the climate details in depth to provide you with a complete overview.

Average day and night temperature

Visitors to SeaTac can expect significant temperature changes throughout the year. Typically, daytime temperatures range from a comfortable 25°C in July to a chilly 8°C in the coolest month, December. Nights are cooler, with temperatures generally dropping to 2°C, particularly during the colder months.

The mean minimum and maximum temperatures throughout the year

Precipitation and rainy days

SeaTac is known for its substantial rain/snowfall, with annual precipitation reaching 1006 mm. The climate in SeaTac shows significant variation throughout the year. Expect heavy rainfall in November, with an average of 165 mm of precipitation over 20 rainy days. In contrast, July offers drier and sunnier days, with around 14 mm of rainfall over 4 rainy days.

The mean monthly precipitation over the year, including rain, hail and snow

Sunshine over the year

For those who appreciate different seasons, SeaTac serves as an ideal destination. Expect longer, more sun-filled days in July with an average of 10.4 hours of sunshine daily, and embrace the darker days in December, offering only 1.8 hours of daily sunlight.

Monthly hours of sunshine


Daily hours of sunshine


The best time of year to visit SeaTac in the United States of America

During the months of June, July, August and September you are most likely to experience good weather with pleasant average temperatures that fall between 20°C and 26°C.

Other facts from our historical weather data:
  • Which is the warmest month in SeaTac?
    July has an average maximum temperature of 25°C and is the warmest month of the year.
  • Which is the coldest month in SeaTac?
    The coldest month is December with an average maximum temperature of 8°C.
  • Which is the wettest month in SeaTac?
    November tops the wettest month list with 165 mm of rainfall.
  • Which is the driest month in SeaTac?
    July is the driest month with 14 mm of precipitation.
  • Which is the sunniest month in SeaTac?
    July is the sunniest month with an average of 312 hours of sunshine.

  • No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.

    Forecast for SeaTac (WA)

    Sat   Nov 23
    10°C | 5°C
    SW 18 km/h
    0.9 mm
    broken clouds and  chance of rain

    broken clouds and chance of rain

    Sun   Nov 24
    8°C | 5°C
    E 11 km/h
    28 mm
    overcast and heavy rain

    overcast and heavy rain

    Mon   Nov 25
    9°C | 5°C
    E 11 km/h
    5.3 mm
    overcast and heavy rain

    overcast and heavy rain