August 21 is statistically one of the best days of the year in Lisbon. With minimal rain risk (0%) and pleasant highs of 28°C, it's ideal for outdoor adventures. As it's peak season for Lisbon, we recommend booking your stay well in advance to secure the best rates.
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Essential Travel Info for Lisbon
Currency
EUR
€ Euro
Language
Portuguese
Driving
Right side
Connect
All of Lisbon has 4G from all Portuguese...
Safety
Very High Safety
GPI: 1.301
Lisbon Weather Forecast for August 21
"Warm & Sunny. Expect average highs of 27.9°C. 0% chance of rain."
What to Wear in Lisbon in August
Based on historical data for August 21, Lisbon typically experiences temperatures between 18.6°C and 27.9°C. We recommend packing t-shirt, light clothing to stay comfortable. Trends suggest it will stay mostly dry (0% rain probability), but checking the forecast before heading out is always wise.
Complete Packing Guide
Weekly breakdown & essential items for Lisbon
Smart Suitcase
- T-Shirt
- Light Clothing
Average High
27.9°C
Daytime Peak
Average Low
18.6°C
Nighttime Low
Feels Like
30.2°C
🔥 Feels warmer
Rain Chance
0%
Avg 0mm if it rains
Cloud Cover
23%
Overcast
Pressure
1016.3 hPa
Low volatility
Lisbon Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 93% 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
🔴 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
21.4°C
Humid/Sticky
Heat Index
30.2°C
Feels hotter
🙂 Best outdoor time:
Any time during daylight hours
Marine Conditions
Marine Life
No special warnings. Enjoy the swim!
Swim Index
⚠️ Mixed Conditions
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in Portugal
Flight Traffic
High
99/100 pressure index
Health Advisory
Required
1 vaccine • View Details →
Landing Slots
~1,242
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Lisbon
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
05:57
☀️ Noon
12:41
🌇 Sunset
19:25
⏱️ Daylight
13h 28m
Wind Speed
23.2 km/h
Moderate wind
Sunshine
12.0 hrs
Direct Sun (Cloud-free)
Humidity
68%
Slightly humid
Travel Intelligence
Exclusive flight analytics & health data for Lisbon
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 Lisbon
Travel Comfort Index
Real-time tourism conditions
Weather Quality
☀️ Excellent
Tourist Crowds
🔴 Very 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 excellent. Perfect for outdoor activities.
Regional Safety Profile
Seismic Activity
Rare minor tremors. Buildings are earthquake-resistant.
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Lisbon on August 21 averages 27.9°C with a 0% precipitation probability. Wedding/Outdoor Event Score: 100/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Lisbon Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Compare Other Cities
Same date (August 21) in other destinations
🌍 Explore the same date in different destinations around the world
📍 Is Lisbon Worth Visiting on August 21?
Planning a trip to Lisbon on August 21? Our historical weather analysis based on 30 years of NASA satellite data shows that this time of year typically offers vibrant summer conditions averaging 27.9°C with a 0% historical precipitation risk.
✈️ Travel Logistics: Approximately 1,242 landing slots available daily during this period, indicating peak tourist activity.
💉 Health Advisory: 6 vaccinations are recommended for Portugal, including COVID-19.
🌊 Coastal Conditions: Water temperature averages 19.8°C (refreshing tonic). Wave conditions are generally fun waves with heights around 0.79m.
📊 Historical Extremes: The hottest August 21 recorded in the last 30 years saw temperatures hit 37.4°C in 2023, while the coldest dropped to 16.4°C in 2021.