April 21 is generally a great time to visit Seattle. While there is a slight chance of rain (31%), showers are usually brief. Expect comfortable 14°C weather. Expect a bustling atmosphere in Seattle right now—this is when the city truly comes alive with visitors.
View the full calendar
Essential Travel Info for Seattle
Currency
USD
$ United States dollar
Language
English
Driving
Right side
Connect
The area code for the City of Seattle is...
Safety
Moderate Safety
GPI: 2.44
Seattle Weather Forecast for April 21
"Mild & Comfortable. Expect average highs of 14.3°C. 31% chance of rain."
What to Wear in Seattle in April
Based on historical data for April 21, Seattle typically experiences temperatures between 5.5°C and 14.3°C. We recommend packing heavy coat, scarf, gloves along with other layers to stay comfortable. With a 31% chance of rain, keeping a raincoat or umbrella handy is a smart move.
Complete Packing Guide
Weekly breakdown & essential items for Seattle
Smart Suitcase
- Heavy Coat
- Scarf
- Gloves
- Umbrella
Average High
14.3°C
Daytime Peak
Average Low
5.5°C
Nighttime Low
Feels Like
14.1°C
🌤️ Feels accurate
Rain Chance
31%
Avg 2.2mm if it rains
Cloud Cover
62%
Overcast
Pressure
1018.5 hPa
Medium volatility
Seattle Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 91% of the time. Safe to plan outdoor activities with confidence.
Sun Exposure
UV Index & Safety Guide
Protection Needed
SPF 30 recommended
05:00 - 10:00
16:00 - 19:00
Type I-II
🔴 23 min to burn
Type III-IV
🟡 35 min to burn
Type V-VI
🟢 58 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
10.1°C
Pleasant
Heat Stress
Low
No heat warning
🙂 Best outdoor time:
Any time during daylight hours
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in United States
Flight Traffic
High
80/100 pressure index
Health Advisory
Healthy
Routine only • View Details →
Landing Slots
~595
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Seattle
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
05:10
☀️ Noon
12:09
🌇 Sunset
19:07
⏱️ Daylight
13h 57m
Wind Speed
13.5 km/h
Gentle breeze
Sunshine
9.5 hrs
Direct Sun (Cloud-free)
Humidity
76%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Seattle
Smart Flight Estimator
Airport-to-Airport Logistics
unlock smart flight estimates
Add your home location in settings to see airport details.
Travel Health & Safety in Seattle
Travel Comfort Index
Real-time tourism conditions
Weather Quality
⛅ Good
Tourist Crowds
🟡 Busy
Price Level
💰💰 Moderate
Health & Wellbeing
Meteo-Health Forecast
Moderate fluctuations. Some sensitivity possible.
Weather unlikely to affect joint pain.
Moderate fish activity expected.
Air quality is excellent. Perfect for outdoor activities.
Regional Safety Profile
Seismic Activity
Rare minor tremors. Buildings are earthquake-resistant.
Volcanic Activity
Nearest: Mount Rainier
94.3km away
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Seattle on April 21 averages 14.3°C with a 31% precipitation probability. Wedding/Outdoor Event Score: 85/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Seattle Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Better Alternatives Nearby
Consider these dates within ±7 days
April 23
14.5°C • 27% rain
Score
88
April 25
14.7°C • 29% rain
Score
88
April 28
14.9°C • 30% rain
Score
88
💡 Moving your event by a few days could significantly improve weather conditions
Compare Other Cities
Same date (April 21) in other destinations
🌍 Explore the same date in different destinations around the world
📍 Is Seattle Worth Visiting on April 21?
Planning a trip to Seattle on April 21? Our historical weather analysis based on 30 years of NASA satellite data shows that this time of year offers a bracing seasonal atmosphere averaging 14.3°C with a 31% historical precipitation risk.
✈️ Travel Logistics: Approximately 595 landing slots available daily during this period, indicating peak tourist activity.
📊 Historical Extremes: The hottest April 21 recorded in the last 30 years saw temperatures hit 21.3°C in 2016, while the coldest dropped to 4.2°C in 2022.