September 18 is generally a great time to visit Lisbon. While there is a slight chance of rain (16%), showers are usually brief. Expect comfortable 25°C weather. 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 September 18
"Mild & Comfortable. Expect average highs of 24.8°C. 16% chance of rain."
What to Wear in Lisbon in September
Based on historical data for September 18, Lisbon typically experiences temperatures between 17.5°C and 24.8°C. We recommend packing t-shirt, light clothing to stay comfortable. Trends suggest it will stay mostly dry (16% 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
24.8°C
Daytime Peak
Average Low
17.5°C
Nighttime Low
Feels Like
25.5°C
☀️ Feels accurate
Rain Chance
16%
Avg 0.9mm if it rains
Cloud Cover
37%
Overcast
Pressure
1015.9 hPa
Medium volatility
Lisbon Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 96% of the time. Safe to plan outdoor activities with confidence.
Sun Exposure
UV Index & Safety Guide
Protection Needed
SPF 30 recommended
06:00 - 10:00
16:00 - 18:00
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
19.4°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
⚠️ Mixed Conditions
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in Portugal
Flight Traffic
High
100/100 pressure index
Health Advisory
Required
1 vaccine • View Details →
Landing Slots
~1,253
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Lisbon
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
06:21
☀️ Noon
12:32
🌇 Sunset
18:42
⏱️ Daylight
12h 20m
Wind Speed
20.2 km/h
Moderate wind
Sunshine
10.3 hrs
Direct Sun (Cloud-free)
Humidity
72%
Humid / Damp
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
🟡 Busy
Price Level
💰💰💰 Expensive
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.
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Lisbon on September 18 averages 24.8°C with a 16% precipitation probability. Wedding/Outdoor Event Score: 99/100."
— 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
Better Alternatives Nearby
Consider these dates within ±7 days
September 11
25.9°C • 10% rain
Score
100
September 12
25.9°C • 10% rain
Score
100
September 13
25.8°C • 11% rain
Score
100
💡 Moving your event by a few days could significantly improve weather conditions
Compare Other Cities
Same date (September 18) in other destinations
🌍 Explore the same date in different destinations around the world
📍 Is Lisbon Worth Visiting on September 18?
Planning a trip to Lisbon on September 18? 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 24.8°C with a 16% historical precipitation risk.
✈️ Travel Logistics: Approximately 1,253 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 18.4°C (refreshing tonic). Wave conditions are generally fun waves with heights around 0.84m.
📊 Historical Extremes: The hottest September 18 recorded in the last 30 years saw temperatures hit 29.9°C in 2025, while the coldest dropped to 13.8°C in 2017.