Weather in Seattle 🇺🇸
Monthly weather averages & travel planning
May
Avg Temp
18°C
Rain Days
13 days
Sun Hours
11 hrs
Humidity
65%
North America › 🇺🇸 United States › Seattle
Updated: March 2026
Is May a Good Time to Visit Seattle?
6/10
Good
May is a good time to visit Seattle (6/10). With 11 daily sunshine hours and only 13 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 4th sunniest of the year in Seattle. Culture-focused travellers and those who prefer lighter crowds will find May a practical choice, with prices running lower than peak July without sacrificing all the good weather. April offers a similar profile at lower hotel rates if dates are flexible. The main practical note: Seattle's popular sites are busiest between 10am and 3pm regardless of season. Arriving at opening time or after 4pm makes a significant difference to the experience. Planning tips: accommodation is generally available without long lead times, and flight prices are typically lower than peak season. Flexible travellers will find the best deals by booking 2-4 weeks ahead. Mid-week arrivals consistently unlock lower hotel rates than weekend check-ins.
vs April:14°C avg high
Seattle in May rewards travelers with average highs of 18°C and overnight lows around 8°C. Expect around 13 rainy days, so a compact umbrella is worth carrying. With 11 daily sunshine hours on average, conditions are comfortable for sightseeing at a relaxed pace.
18°C
64°F
Avg High
8°C
46°F
Avg Low
13 days
76 mm total
Rain Days
11h
per day avg
Sunshine
65%
Moderate
Humidity
Temperature in Seattle in May
The 10°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 10 this month, classed as high to very high. SPF 30+ sunscreen, a brim hat, and sunglasses are not optional between 10am and 4pm. Winds are calm at an average 14 km/h, so wind-chill is not a factor in planning your clothing. In Fahrenheit: 64°F average high, 46°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Temperature Trends
High
Low
Rainfall (mm)
0-20 mm21-50 mm51-100 mm100+ mm
What to Wear in Seattle in May
Morning8°CBefore the day warms up
Afternoon18°CPeak daytime temperature
Evening11°CAfter sunset cools down
Packing for Seattle in May means dressing for 18°C days and 8°C evenings. A mid-weight jacket over a sweater handles 18°C daytime temperatures; the combination stays comfortable all day without overheating. Evening temperatures settle at 8°C, a modest 10°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 13 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: Layers are more practical than a single heavy garment in Seattle. The day-to-evening temperature shift rewards packing a versatile mid-layer you can add or remove as conditions change.
Events in Seattle in May
May 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.
What to Pack for Seattle in May
Based on 18°C average highs and 13 rainy days
- Light jacket or cardigan for cooler evenings
- Mix of short and long-sleeve layers
- Comfortable walking shoes with good arch support
- Compact folding umbrella
- Waterproof outer layer or packable rain jacket
- Quick-dry clothing that recovers fast after a shower
- Universal travel adapter
- Small day pack for city exploration
- Reusable water bottle
Best Activities in Seattle in May
- Explore the old town's cobblestone backstreetsMorning (9-11am)At 18°C, conditions are pleasant for unhurried exploration on foot
- Visit hilltop viewpoints for panoramic city viewsLate afternoon (4-6pm)Low sun angle creates dramatic light for photography while temperatures remain comfortable
- Bicycle rental for a half-day city circuitMid-morning startMild 18°C temperatures are ideal for extended cycling without excessive effort
- Boat tour of the river, bay, or canal networkLate morning departureComfortable weather makes open-deck boats viable without wind-chill concerns
- Spend a morning in the national or city art museumOpens at 10am; arrive earlyWith 13 rain days expected, having a full-day indoor plan is practical insurance
- Cooking class focused on regional cuisineHalf-day sessions run 10am-1pm or 3-6pmIndoor activity that fills a rainy half-day with genuine cultural content
- Visit covered historical sites: cathedral, palace, or bazaarAny time; most crowded middayRoofed monuments and covered markets provide exploration without weather exposure
- Visit the main botanical garden or city park at seasonal peakYear-round; best light in morningMay brings distinct seasonal changes to public green spaces worth exploring
- Try the seasonal farmer's market for local produce and street foodSaturday morning markets typically 8am-1pmMay seasonal produce is at peak availability, offering dishes not found at other times of year
Why is Seattle mild in May?
May marks the transition into warmer conditions in Seattle, as the sun angle climbs and day length extends. Temperatures averaging 18°C by day and 8°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 May 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.
Frequently Asked Questions
Seattle in May
In May, Seattle experiences average highs of 18°C (64°F) and lows of 8°C (46°F). Expect around 13 rainy days and 11 hours of sunshine per day, with humidity averaging 65%. The 10°C gap between daytime and overnight temperatures is worth planning around: light layers work for most visitors during the day, but an extra jacket is essential for evenings. UV index averages 10, so sun protection is advisable on clear days.
Seattle typically sees 13 rainy days in May, with total precipitation of around 76mm. Rain is moderate and manageable. Showers tend to pass quickly, and a light rain layer or foldable umbrella is sufficient protection for most days. For context, the driest month in Seattle typically sees 4-6 fewer rain days than May.
Pack a warm jacket, sweaters, and layering pieces for Seattle in May. Temperatures can drop to 8°C at night, so thermal underlayers are advisable for evening outings. Waterproof footwear is important with 13 rainy days expected. A scarf, hat, and gloves handle the windchill on clear cold days, which often feel colder than the thermometer reads.
May is a reasonable time to visit Seattle. Expect 13 rainy days, so pack a light rain layer for flexibility. Average temperatures of 18°C make outdoor exploration comfortable during the dry periods. With 11 daily sunshine hours, there are reliable windows of good weather to plan outdoor activities around, even if the month is not the driest on the calendar.
The average high temperature in Seattle in May is 18°C (64°F), and the average low is 8°C (46°F). The mean daily temperature is approximately 13°C (55°F). The day-to-night range of 10°C is moderate, meaning a single light jacket covers most situations. These are 30-year climate normals based on the 1991 to 2020 reference period; individual years will vary, particularly in transitional months like spring and autumn.
The best month to visit Seattle is generally July. July offers the most sunshine at 13 hours per day and only 6 rainy days. Average temperatures reach 25°C, making it comfortable for sightseeing, outdoor dining, and exploring the city. If your travel dates are flexible, planning your trip around July gives you the best chance of dry, bright weather.
May is shoulder or low season in Seattle, meaning fewer tourists and generally lower prices than peak months. With 11 sunshine hours and 13 rainy days, the weather is less of a draw for mass tourism. This is an advantage for travellers who prefer a quieter, more relaxed experience with shorter queues and easier accommodation availability.
In May, Seattle suits a range of activities thanks to cool conditions around 18°C. Mix of indoor and outdoor activities works well given the moderate chance of rain. Top options include exploring historic neighbourhoods, visiting museums and galleries, local food markets, and day trips to surrounding areas. With 11 hours of sunshine, parks and waterfront walks are particularly enjoyable.
May ranks 4th sunniest of the year in Seattle, with an average 11 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 3°C into June. Compared to last month (April: 14°C high, 16 rain days), May is warmer and drier. May sits in the middle of the annual sunshine ranking for Seattle, offering a reasonable balance of good weather and manageable crowds.
Year-Round Climate
| 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
8°2°
February
14 rain days, 6h sun
9°2°
March
18 rain days, 8h sun
11°3°
April
16 rain days, 10h sun
14°5°
May
13 rain days, 11h sun
18°8°
June
10 rain days, 12h sun
21°11°
July
6 rain days, 13h sun
25°14°
August
5 rain days, 12h sun
25°14°
September
8 rain days, 10h sun
21°12°
October
15 rain days, 7h sun
15°8°
November
18 rain days, 5h sun
10°4°
December
18 rain days, 4h sun
7°2°
Other Months in Seattle
Plan Your Trip to Seattle
Data Sources for Seattle
Climate normals represent 30-year averages (1991-2020). Individual years may vary.