Seattle Weather
A month-by-month look at temperature, rainfall and what to pack in Seattle. The annual average is 15°C high / 8°C low — hottest in July (peak month) (24°C) and coldest in January (3°C).
Seattle Weather at a Glance
As of 2026A quick summary of Seattle's year-round climate and the best time to visit.
- Annual average
- 15° / 8°
- Best time to visit
- July (peak month), August, September (sleeper-best month)
- Hottest month
- July (peak month) (24°C)
- Coldest month
- January (3°C)
- Wettest month
- November (175mm)
- Driest month
- July (peak month) (18mm)
As of 2026, Seattle's weather averages 15°C high / 8°C low across the year, and the best time to visit for stable temperatures, rainfall and crowds is July (peak month), August, September (sleeper-best month). The hottest month is July (peak month) (24°C), the coldest is January (3°C), and the wettest is November (175mm).
Best Time to Visit Seattle
**July is the single best month to visit Seattle.** Mostly sunny + warm + only 3 rainy days/month. Mt Rainier Paradise wildflower meadows peak (Jul-Aug). Long daylight (16+ hours) maximizes sightseeing. Hotel prices + crowds also peak — book 1+ month ahead.
August continues peak July. **Seafair Weekend** (1st weekend) brings hydroplane races on Lake Washington + US Navy Blue Angels jets in the sky. Outdoor concerts run all month. Mt Rainier wildflowers still peak. Watch wildfire smoke days (more common years 2020-2023).
**September is the sleeper-best Seattle month.** Weather still warm + mostly dry (similar to August) but hotel rates drop 30% from August + crowds thin. **Bumbershoot Music Festival** (Labor Day weekend) is the city's signature music event. Mt Rainier still accessible (wildflowers ending; foliage beginning).
Seattle Weather Month by Month
Tap any month for a detailed guide with what to wear, sunrise/sunset and air quality.
| Month | High/Low | Rain | Rainy days | Crowds | |
|---|---|---|---|---|---|
| January | 8° / 3° | 145mm | 18 | Quiet | Details → |
| February | 10° / 4° | 110mm | 16 | Quiet | Details → |
| March | 12° / 5° | 100mm | 16 | Moderate | Details → |
| April | 14° / 6° | 80mm | 14 | Moderate | Details → |
| May | 17° / 9° | 50mm | 10 | Busy | Details → |
| June | 20° / 11° | 38mm | 8 | Very busy | Details → |
| July (peak month) | 24° / 13° | 18mm | 3 | Very busy | Details → |
| August | 24° / 13° | 22mm | 4 | Very busy | Details → |
| September (sleeper-best month) | 21° / 11° | 38mm | 7 | Busy | Details → |
| October | 15° / 8° | 90mm | 13 | Moderate | Details → |
| November | 11° / 5° | 175mm | 19 | Quiet | Details → |
| December (holiday season) | 8° / 3° | 145mm | 18 | Busy | Details → |
What to Wear in Seattle by Season
Spring — high 14°C, low 6°C. Light layers + waterproof shell. UV beginning to matter; sunglasses + light sunscreen.
Peak summer — high 24°C, low 13°C. T-shirt all day; light layer for cool evenings. Sunscreen mandatory.
Autumn — high 15°C, low 8°C. Light waterproof jacket + sweater. Daylight saving ends first Sunday of November (clocks back 1h).
Late winter — high 10°C, low 4°C. Same layering as January. Some clearing afternoons.
Seattle Weather FAQ
What is the best time to visit Seattle? +
For weather, July (peak month), August, September (sleeper-best month) are the most comfortable months. Highs sit around 24°C with relatively stable rainfall and crowds.
What are the hottest and coldest months in Seattle? +
The hottest month is July (peak month) with an average high of 24°C, and the coldest is January with an average low of 3°C. The annual average is 15°C high / 8°C low.
When does it rain most in Seattle? +
The wettest month is November (175mm over about 19 rainy days) and the driest is July (peak month) (18mm). Total annual rainfall is roughly 1011mm.
What should I pack for Seattle? +
Spring (Mar–May) averages 14/7°C — Spring — high 14°C, low 6°C. Light layers + waterproof shell. UV beginning to matter; sunglasses + light sunscreen. Summer (Jun–Aug) averages 23/12°C — Peak summer — high 24°C, low 13°C. T-shirt all day; light layer for cool evenings. Sunscreen mandatory. Autumn (Sep–Nov) averages 16/8°C — Autumn — high 15°C, low 8°C. Light waterproof jacket + sweater. Daylight saving ends first Sunday of November (clocks back 1h). Winter (Dec–Feb) averages 9/3°C — Late winter — high 10°C, low 4°C. Same layering as January. Some clearing afternoons.
What is the weather in Seattle this month (June)? +
June averages 20°C high / 11°C low with 38mm rainfall over about 8 rainy days. Crowds are very busy and prices are high.
Keep Planning Your Seattle Trip
Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.