May 21 is statistically one of the best days of the year in Istanbul. With minimal rain risk (14%) and pleasant highs of 22°C, it's ideal for outdoor adventures. It's a lively time to explore Istanbul, with most attractions operating at full capacity.
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Essential Travel Info for Istanbul
Currency
TRY
₺ Turkish lira
Language
Turkish
Driving
Right side
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Safety
Travel Precautions
GPI: 2.785
Istanbul Weather Forecast for May 21
"Mild & Comfortable. Expect average highs of 22.2°C. 14% chance of rain."
What to Wear in Istanbul in May
Based on historical data for May 21, Istanbul typically experiences temperatures between 14.3°C and 22.2°C. We recommend packing t-shirt, light clothing to stay comfortable. Trends suggest it will stay mostly dry (14% rain probability), but checking the forecast before heading out is always wise.
Complete Packing Guide
Weekly breakdown & essential items for Istanbul
Smart Suitcase
- T-Shirt
- Light Clothing
Average High
22.2°C
Daytime Peak
Average Low
14.3°C
Nighttime Low
Feels Like
22.6°C
☀️ Feels accurate
Rain Chance
14%
Avg 0.7mm if it rains
Cloud Cover
44%
Overcast
Pressure
1013.4 hPa
Low volatility
Istanbul Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 86% 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 - 20:00
Type I-II
🔴 14 min to burn
Type III-IV
🟡 21 min to burn
Type V-VI
🟢 35 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
17.3°C
Noticeable
Heat Stress
Low
No heat warning
😊 Best outdoor time:
Any time during daylight hours
Marine Conditions
Marine Life
No special warnings. Enjoy the swim!
Swim Index
❄️ Cold Water Hazard
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in Turkey
Flight Traffic
Busy
60/100 pressure index
Health Advisory
Required
2 vaccines • View Details →
Landing Slots
~761
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Istanbul
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
05:42
☀️ Noon
13:02
🌇 Sunset
20:21
⏱️ Daylight
14h 38m
Wind Speed
17.6 km/h
Gentle breeze
Sunshine
12.0 hrs
Direct Sun (Cloud-free)
Humidity
74%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Istanbul
Smart Flight Estimator
Airport-to-Airport Logistics
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Travel Health & Safety in Istanbul
Travel Comfort Index
Real-time tourism conditions
Weather Quality
☀️ Excellent
Tourist Crowds
🟡 Busy
Price Level
💰💰💰 Expensive
Health & Wellbeing
Meteo-Health Forecast
Stable conditions. Low risk of headaches.
Weather unlikely to affect joint pain.
Moderate fish activity expected.
Air quality is acceptable. Sensitive individuals should limit prolonged outdoor exertion.
Regional Safety Profile
Seismic Activity
Moderate seismic activity. Occasional tremors possible.
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Istanbul on May 21 averages 22.2°C with a 14% precipitation probability. Wedding/Outdoor Event Score: 100/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Istanbul Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Compare Other Cities
Same date (May 21) in other destinations
🌍 Explore the same date in different destinations around the world
📍 Is Istanbul Worth Visiting on May 21?
Planning a trip to Istanbul on May 21? Our historical weather analysis based on 30 years of NASA satellite data shows that this time of year is characterized by pleasant mild weather averaging 22.2°C with a 14% historical precipitation risk.
✈️ Travel Logistics: Approximately 761 landing slots available daily during this period, indicating peak tourist activity.
💉 Health Advisory: 7 vaccinations are recommended for Turkey, including COVID-19.
🌊 Coastal Conditions: Water temperature averages 16°C (polar plunge). Wave conditions are generally lake-like with heights around 0.18m.
📊 Historical Extremes: The hottest May 21 recorded in the last 30 years saw temperatures hit 27.5°C in 2025, while the coldest dropped to 9.2°C in 2022.