SeaTac

Stay up to date with the latest weather conditions in the city of SeaTac. Below, you'll find current data, forecasts, and helpful weather charts to help you plan your day.

The climate in SeaTac, USA, can be described as temperate marine. It is characterized by mild, wet winters and warm, relatively dry summers. Annual temperature fluctuations are not too extreme, making the weather generally comfortable for visiting throughout the seasons, though seasonal precipitation patterns should be taken into account.

There are four distinct seasons in SeaTac. Winter (December–February) is cool, with average temperatures around 5-6°C, and is the wettest time of year—precipitation is frequent, with the number of rainy days reaching 18-21 per month. Spring (March–May) brings gradual warming, with average temperatures rising from 7°C to 14°C, while precipitation decreases. Summer (June–August) is the warmest and sunniest time of year. Average temperatures hover around 17-20.5°C, with highs reaching a comfortable 25°C. July and August are the driest months, with minimal rainfall and only 4-6 rainy days. Autumn (September–November) is characterized by a gradual temperature drop from 17.5°C to 8°C and an increase in rainy days, preparing the city for the wet winter.

Thus, when planning a trip to SeaTac, you can expect a warm and mostly dry summer, ideal for outdoor activities and sightseeing. In contrast, the winter months will be cool and rainy, which should be considered when choosing your wardrobe. The shoulder seasons offer moderate temperatures with varying chances of precipitation.

The climate in SeaTac is characterized by moderate temperatures throughout the year, with noticeable seasonal variations. The warmest month is typically August, when the average temperature reaches 20.5°C and daytime highs average around 25.8°C. The coldest month is usually February, with an average temperature of 5.1°C and average nightly lows dropping to 2.4°C. Overall, the annual cycle of average monthly temperatures ranges from about 5°C in winter to just over 20°C at the height of summer.

The summer months, especially July and August, bring pleasant warmth to SeaTac. Daytime temperatures during this period often rise to 25-26°C, creating comfortable conditions for walking and outdoor activities. At the same time, nights remain relatively cool, with average minimum temperatures around 15°C. This difference between day and night temperatures, reaching 10-11°C, is a characteristic feature of the summer period, providing freshness in the evenings and at night. Transitional seasons, spring and autumn, are marked by a gradual change in temperatures: for instance, in May the average temperature is about 13.9°C, and in October it is 12.2°C.

Winter in SeaTac, spanning from December to February, is characterized by cool weather but without severe frosts. Average daytime highs during this period fluctuate around 7-8°C, while nightly lows usually stay above freezing, averaging 2-4°C. The lowest average minimum temperatures are observed in February (2.4°C). Daily temperature fluctuations in winter are less pronounced than in summer, at around 4-5°C, but are still noticeable. The weather in the winter months is quite mild, though it does require warm clothing.

SeaTac sees a distinct seasonality in precipitation throughout the year. The wettest period occurs from late autumn to early spring, while summer is marked by significantly less precipitation, creating a clear dry season.

The wettest month in SeaTac is January, with an average of 7 mm of precipitation and up to 21 rainy days. Overall, the period from October to April is characterized by frequent precipitation. For example, November and December each see 6 mm of precipitation, with 18 and 19 rainy days, respectively. Given the relatively low total precipitation despite the high frequency, it can be assumed that this time of year is characterized by long-lasting but not very heavy rain or drizzle.

In contrast, the summer months are the driest in SeaTac. July stands out as almost rainless, with an average of 0 mm of precipitation and only about 4 rainy days. August is also very dry, with 1 mm of precipitation and roughly 6 rainy days. Even in transitional months like May, June, and September, precipitation remains low (2 mm), although the frequency of rainy days is slightly higher than during the peak dry season.

When planning a trip to SeaTac, it's important to be prepared for its characteristically changeable weather and frequent precipitation, especially from October to April. The key principle when packing should be layering, which allows you to adapt to temperature changes throughout the day. Essential companions for almost any time of year are a waterproof jacket or raincoat and a reliable umbrella. Don't forget comfortable, preferably waterproof shoes, as keeping your feet dry is key to enjoying walks around this city in the USA.

During the warmer months, primarily from June to August, when SeaTac enjoys sunny days and average temperatures range from 17-21°C—with daytime highs often reaching 25°C or more—your wardrobe can consist of light T-shirts, shorts, and dresses, along with sunscreen and a hat. However, even summer evenings can be cool, so a light sweater or cardigan will come in handy. For the cooler and rainier period from autumn through spring (roughly September to May), when temperatures usually stay between 5-15°C (and sometimes drop lower, especially at night) and rainy days are frequent, the main focus should be on warm clothing: sweaters, fleece jackets, warm trousers, as well as a hat, gloves, and a scarf. A windbreaker will also be useful for protection against the piercing winds that can accompany the rain.