SeaTac (WA) Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in SeaTac (WA). The numbers are calculated over a 30-year period to provide a reliable average. Now, let’s explore all the details to give you a full picture.

SeaTac has a notably wet climate with abundant precipitation, recording 1006 mm of rain/snowfall per year.

Monthly Precipitation Levels

The average number of days each month with precipitation (> 0.2 mm)

SeaTac can be quite wet during November, receiving approximately 165 mm of precipitation over 20 rainy days.

In contrast July, experiences much drier conditions, with 14 mm of rainfall, spread across 4 rainy days.

November, the city’s wettest month, has a maximum daytime temperature of 11°C and receives 73 hours of sunshine. During the driest month July you can expect a temperature of 25°C. For more detailed insights into the city’s temperatures, visit our SeaTac Temperature page.

Annual Precipitation in the United States of America

The map below shows the annual precipitation across the United States of America. You can also select the different months in case you are interested in a specific month.

Amsterdam Precipitation Compared World Wide

SeaTac’s average annual precipitation is 1006 mm. Let’s compare this to some popular worldwide tourist destinations:

In Toronto, Canada, annual precipitation averages [964 mm], with snowy winters and rainy summers.

In Seoul, South Korea, the average annual precipitation is 1237 mm, with most rain falling during the summer monsoon season.

Perth, Australia, receives 565 mm of rainfall annually, mostly during the winter months.

Ho Chi Minh City, Vietnam, receives 1955 mm of annual rainfall, with a pronounced wet season from May to November, typical of its tropical monsoon climate.

How is Precipitation Measured?

Precipitation amounts are measured using specific gauges installed at weather stations, collecting both rain and snow and any other type of precipitation. Rainfall is measured directly in millimeters, while that from snow and ice is obtained by melting it. Automated systems often incorporate heaters to make this easier.

Information from these stations is transmitted via Wi-Fi, satellite, GPS, or telephone connections to central monitoring networks. This information is immediately updated and integrated into weather models and forecasts.

Global Warming and Precipitation

Climate change is affecting precipitation patterns worldwide, including SeaTac (WA):

• Changing Rainfall Patterns: Global warming causes drastic changes in the patterns of rainfall. Some areas have been experiencing increased frequency and intensity of rainfall, while other areas experience longer dry spells or even droughts.
• Local Impacts: Many regions are experiencing heavier rainfall in the winter months and drier, hotter summers. This affects agriculture, water resources, and ecosystems.

For more detailed information about SeaTac (WA)’s weather, including sunshine hours, humidity levels, and temperature data, visit our SeaTac (WA) Climate page.