Question 1

When is the sunniest time of year in Seattle?

Accepted Answer

The sunniest time of year in Seattle is summer, with July 2025 standing out as the brightest month by far, recording 400.2 hours of sunshine.

Across the meteorological summer (June to August 2025), Seattle soaked up 1,033.8 hours of sunshine, averaging about 345 hours per month. July led the way with 400.2 hours — roughly 12.9 hours of sun per day — followed by August at 352.8 hours and September at 296.9 hours. This sunny stretch coincided with Seattle's driest spell: July saw just 2.4 mm (0.09 inches) of rain, a dramatic contrast to the gray, wet winter months.

The difference between the seasons is striking. December 2025 was the darkest month with only 68.3 hours of sunshine, while December's rainfall reached 243.6 mm (9.6 inches). Over the full year, Seattle accumulated 2,465.7 hours of sunshine, meaning summer alone delivered more than 40% of the annual total.

For visitors and locals planning outdoor activities, the takeaway is clear: mid-July through August offers Seattle's most reliable sunshine and warmth, with daytime highs frequently in the high 20s°C (low 80s°F). If you want to experience Seattle at its brightest and driest, the July–September window is the ideal time to enjoy the city's parks, waterfront, and mountain views.

Question 2

How much rainfall does Seattle get per year, and which months are wettest?

Accepted Answer

Seattle received a total of **1,180.6 mm (46.5 inches)** of rainfall across 2025, confirming the city's well-earned reputation for wet weather. The rain was heavily concentrated in the late-autumn and early-winter months rather than spread evenly through the year.

December 2025 was by far the wettest month in Seattle, delivering 243.6 mm (9.6 in) of precipitation, followed closely by November with 202.2 mm (8.0 in) and March with 174.0 mm (6.9 in). At the other extreme, July 2025 was remarkably dry, recording just 2.4 mm (0.1 in) — essentially a rain-free month.

The seasonal contrast in Seattle is striking. The three summer months (June–August) produced only 47.0 mm (1.9 in) combined, accounting for just 4% of the year's rainfall. By comparison, the October–December stretch alone brought 596.4 mm (23.5 in), more than half of Seattle's entire annual total.

For visitors and residents, this pattern has clear practical implications. If you want to experience Seattle at its driest, plan trips and outdoor activities for July and August, when rainfall is minimal and skies are typically clear. Conversely, the period from late October through December calls for a reliable rain jacket and waterproof footwear, as steady precipitation becomes the norm. Understanding this strong seasonal rhythm makes it much easier to time outdoor plans around Seattle's distinctive wet-and-dry climate.

Question 3

What were the temperature extremes in Seattle in 2025?

Accepted Answer

Seattle's temperature extremes in 2025 ranged from a high of 32.5°C (90.5°F) to a low of -6.1°C (21.0°F), giving the city an annual swing of about 38.6°C (69.5°F).

The hottest day in Seattle came on September 16, 2025, when the temperature peaked at 32.5°C (90.5°F). The coldest moment of the year arrived on February 11, 2025, with an overnight low of -6.1°C (21.0°F), which was also the city's chilliest day overall at a daily average of -2.1°C (28.2°F). Across the full year, Seattle's mean temperature settled at a mild 11.1°C (52.0°F).

Genuinely hot weather was rare. Seattle recorded only 2 days at or above 30°C (86°F) in 2025, though 32 days reached 25°C (77°F) or warmer, mostly clustered in summer. On the cold end, the city saw 30 days with frost (lows at or below 0°C/32°F), but not a single day stayed below freezing around the clock.

These figures highlight Seattle's famously moderate maritime climate. With most of the year sitting between mild and cool, residents and visitors rarely face dangerous heat or deep cold. The handful of warm September days and the brief February cold snap mark the practical boundaries to plan around, while the bulk of 2025 offered comfortable, temperate conditions ideal for year-round outdoor activity.

Question 4

When is the windiest time of year in Seattle?

Accepted Answer

Seattle is windiest during the late autumn and winter months, with December 2025 recording the strongest average winds of the year at 12.9 km/h (8.0 mph). Wind speeds in Seattle stay gentle overall, but they clearly pick up as the wet season takes hold.

Based on 2025 monthly data, the city's average wind speed across the full year was just 10.0 km/h (6.2 mph). The windiest stretch ran from the cool, stormy half of the year: December led at 12.9 km/h (8.0 mph), followed by March at 12.3 km/h (7.6 mph) and February at 11.3 km/h (7.0 mph). By contrast, the calmest months were January at 7.5 km/h (4.7 mph) and September at 8.4 km/h (5.2 mph).

Looking at it by meteorological season in 2025, spring (March–May) was the breeziest period overall at 10.8 km/h (6.7 mph), while summer (June–August) was the gentlest at 9.3 km/h (5.8 mph).

For most visitors, Seattle's winds are light enough to be a non-issue year-round. If you prefer the calmest conditions for boating on the lakes or walking the waterfront, the mid-to-late summer months are your best bet, whereas the stronger, gustier weather tends to arrive alongside the heavier rains of December and early spring.

Question 5

What are the average summer temperatures in Seattle?

Accepted Answer

Seattle enjoyed mild average summer temperatures of around 17.5°C (63.5°F) during the meteorological summer of 2025 (June 1 to August 31), making it one of the most comfortable warm seasons among major U.S. cities.

The summer warmed steadily through the season. June was the coolest month with an average of 15.7°C (60.3°F), July climbed to 17.8°C (64.0°F), and August was the warmest at 19.0°C (66.2°F). Daytime highs were pleasantly warm rather than hot, with monthly peak temperatures reaching:

- **June 2025:** up to 27.8°C (82.0°F)
- **July 2025:** up to 31.0°C (87.8°F), the hottest reading of the summer
- **August 2025:** up to 29.7°C (85.5°F)

Nights stayed cool and refreshing throughout, dipping as low as 6.0°C (42.8°F) in June. Average humidity across the season held at a moderate 70.3%, keeping the warmth from feeling oppressive even on the hottest afternoons.

These figures show why Seattle is such a popular summer destination. With typical highs in the comfortable 27–31°C (82–88°F) range and crisp evenings, the 2025 summer was ideal for hiking, kayaking on Lake Washington, and exploring the city on foot. Visitors planning a trip can expect warm, dry afternoons and cool nights, so packing a light jacket for the evenings is always a smart idea in Seattle.

University

Washington

FAQ

When is the sunniest time of year in Seattle?

How much rainfall does Seattle get per year, and which months are wettest?

What were the temperature extremes in Seattle in 2025?

When is the windiest time of year in Seattle?

What are the average summer temperatures in Seattle?