Monthly weather averages & travel planning

North America › 🇺🇸 United States › Seattle
Updated: March 2026
April is a fair time to visit Seattle (4/10). With 10 daily sunshine hours and only 16 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 5th sunniest of the year in Seattle. April suits travellers visiting for indoor culture, food, and architecture rather than outdoor activities. Pack accordingly for 16 potential rain days. March offers a similar profile at lower hotel rates if dates are flexible. Watch out for prolonged rain stretches: with 16 wet days, a fully outdoor itinerary is risky. Build in museum days and covered market visits as contingency. Planning tips: most accommodation categories have availability, and last-minute deals are common. The quieter streets and shorter queues can make this a genuinely enjoyable time to visit for the right type of traveller. Budget-conscious visitors will find the best value of the year in this period.
Seattle in April rewards travelers with average highs of 14°C and overnight lows around 5°C. Expect around 16 rainy days, so a compact umbrella is worth carrying. With 10 daily sunshine hours on average, conditions are cool and bracing, well suited for active days on foot.
14°C
57°F
Avg High
5°C
41°F
Avg Low
16 days
111 mm total
Rain Days
10h
per day avg
Sunshine
65%
Moderate
Humidity
The 9°C day-night temperature range is typical for continental climates: a light jacket in the morning that you shed by midday and need again after sunset. Humidity averages 65%, which is comfortable for most visitors. On warmer days, lighter fabrics help with the mild stickiness in the afternoon. UV index averages 6 this month, classed as moderate. Sunscreen is a sensible precaution for extended outdoor time, particularly at midday. Wind averages 15 km/h, light enough to be refreshing on warm days but noticeable in open coastal areas or elevated viewpoints. In Fahrenheit: 57°F average high, 41°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Packing for Seattle in April means dressing for 14°C days and 5°C evenings. A mid-weight jacket over a sweater handles 14°C daytime temperatures; the combination stays comfortable all day without overheating. Evening temperatures settle at 5°C, a modest 9°C drop that a light cardigan or denim jacket covers. Comfortable walking trainers are the versatile choice for both outdoor sightseeing and indoor venues. With 16 rain days expected, a compact travel umbrella is worth the bag space. A waterproof jacket is better than an umbrella if you plan full-day outdoor routes.
Local tip: Seattle sees heavy rain periods where a compact travel umbrella can feel inadequate. A packable waterproof jacket offers better coverage for prolonged downpours and leaves both hands free for maps and cameras.
April has no major festivals or public holidays in Seattle, which is one of its practical advantages for independent travellers. Attractions run at lower capacity than during peak event periods, queues are shorter, and accommodation is easier to find without needing to book many months in advance. Local restaurants, markets, and transport operate at a relaxed pace, making this an ideal time for visitors who prefer a more authentic, unhurried experience of everyday city life rather than large crowds drawn in by a single major headline event.
Based on 14°C average highs and 16 rainy days
April marks the transition into warmer conditions in Seattle, as the sun angle climbs and day length extends. Temperatures averaging 14°C by day and 5°C overnight reflect a city shaking off winter: the morning air still carries a cool edge, but afternoons are noticeably warmer than even four weeks prior. At 48 degrees north latitude, spring is one of the most dynamic periods in the annual cycle, with weekly temperature changes that can be larger than the month-to-month shifts of summer. This volatility is part of the appeal: Seattle in April has a freshness and energy that peak-summer heat tends to mute. Layers remain essential, but there are reliable pockets of warmth that reward patience. Climate data: Open-Meteo ERA5 (1991–2020).
Sunshine Hours
The average number of hours per day with direct sunlight. Calculated from satellite measurements. Days with more than 7 hours of sunshine are ideal for outdoor activities. Under 3 hours means overcast conditions dominate.
UV Index
A scale from 0-11+ measuring ultraviolet radiation intensity. UV 0-2: Minimal risk. UV 3-5: Moderate, wear sunscreen. UV 6-7: High, hat and SPF 30+ essential. UV 8-10: Very High, limit midday exposure. UV 11+: Extreme, seek shade between 10am-4pm.
Rain Days
A rain day is counted when precipitation exceeds 0.1mm. This threshold captures even light drizzle. Unlike total rainfall in mm, rain days tells you how often you might need an umbrella, which is useful for planning outdoor activities.
Humidity
Relative humidity as a percentage. Below 40%: Dry, skin and throat may feel parched. 40-60%: Comfortable, ideal for most people. 60-80%: Sticky, light breathable fabrics recommended. Above 80%: Muggy, heat feels more intense; quick-dry clothing is essential.
Seattle in April
April ranks 5th sunniest of the year in Seattle, with an average 10 daily sunshine hours. The driest months are August, July, and September. July is the hottest month (25°C avg high); December is the coolest (7°C). From here, temperatures rise 4°C into May. Compared to last month (March: 11°C high, 18 rain days), April is warmer and drier. April sits in the middle of the annual sunshine ranking for Seattle, offering a reasonable balance of good weather and manageable crowds.
| Month | High | Low | Rain Days | Sun | Details |
|---|---|---|---|---|---|
| January | 8°C | 2°C | 18 | 4h | View |
| February | 9°C | 2°C | 14 | 6h | View |
| March | 11°C | 3°C | 18 | 8h | View |
| April | 14°C | 5°C | 16 | 10h | View |
| May | 18°C | 8°C | 13 | 11h | View |
| June | 21°C | 11°C | 10 | 12h | View |
| July | 25°C | 14°C | 6 | 13h | View |
| August | 25°C | 14°C | 5 | 12h | View |
| September | 21°C | 12°C | 8 | 10h | View |
| October | 15°C | 8°C | 15 | 7h | View |
| November | 10°C | 4°C | 18 | 5h | View |
| December | 7°C | 2°C | 18 | 4h | View |
January
18 rain days, 4h sun
February
14 rain days, 6h sun
March
18 rain days, 8h sun
April
16 rain days, 10h sun
May
13 rain days, 11h sun
June
10 rain days, 12h sun
July
6 rain days, 13h sun
August
5 rain days, 12h sun
September
8 rain days, 10h sun
October
15 rain days, 7h sun
November
18 rain days, 5h sun
December
18 rain days, 4h sun
Data Sources for Seattle
Climate normals represent 30-year averages (1991-2020). Individual years may vary.