SeaTac Weather in September

September in SeaTac sees daytime temperatures around 22°C (72°F) and lows of 12°C (54°F) at night. The excellent weather makes it a good time to visit.

Rainfall in SeaTac in September

Typically around 9 days of rainfall are expected, averaging 49 mm (1.9 in) for the month. Expect a fairly normal spread of rainfall this month, with no particular pattern of very heavy or very persistent showers.

Temperature in SeaTac in September

The temperature in SeaTac in September is excellent. Daytime highs reach 22°C (72°F), with nights dropping to 12°C (54°F). The month of September belongs to the summer season. Temperatures can feel cooler in the morning and evening, so layering is often the best approach. Nights drop to around 12°C (54°F), which is noticeably cooler than the daytime. A light jacket for the evening is a sensible addition, and the cool nights tend to make sleeping comfortable.

Sunshine in SeaTac in September

There are approximately 220 hours of sunshine this month, resulting in mostly clear days.

Wind Speed in SeaTac in September

In September, average wind speeds reach 4 m/s (8 knots), leading to light to moderate breezes. Conditions vary from day to day, with both calm and windier periods.

Our weather planner can help you find worldwide destinations with pleasant weather during this period. June, July, August and September typically offer the best weather for SeaTac.