January is the first month it typically snows. Throughout January, in the average 1.3 snowfall days, it receives 0.12″ (3mm) of snow. In Seattle, during the entire year, snow falls for 4.8 days and aggregates up to 0.94″ (24mm) of snow. In January, the average ocean temperature is 45.5°F (7.5°C).
https://www.weather-atlas.com/en/washington-usa/seattle-weather-january