September 21 is generally a great time to visit Naples. While there is a slight chance of rain (24%), showers are usually brief. Expect comfortable 25°C weather. As it's peak season for Naples, we recommend booking your stay well in advance to secure the best rates.
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Essential Travel Info for Naples
Currency
EUR
€ Euro
Language
Italian
+1 more
Driving
Right side
Connect
As of Sept 2021, Naples has 4G from Ilia...
Safety
High Safety
GPI: 1.643
Naples Weather Forecast for September 21
"Warm & Sunny. Expect average highs of 25.2°C. 24% chance of rain."
What to Wear in Naples in September
Based on historical data for September 21, Naples typically experiences temperatures between 17.7°C and 25.2°C. We recommend packing t-shirt, light clothing to stay comfortable. Trends suggest it will stay mostly dry (24% rain probability), but checking the forecast before heading out is always wise.
Complete Packing Guide
Weekly breakdown & essential items for Naples
Smart Suitcase
- T-Shirt
- Light Clothing
Average High
25.2°C
Daytime Peak
Average Low
17.7°C
Nighttime Low
Feels Like
26°C
☀️ Feels accurate
Rain Chance
24%
Avg 1.9mm if it rains
Cloud Cover
45%
Overcast
Pressure
1015.8 hPa
Low volatility
Naples Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 97% 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 - 18:00
Type I-II
🔴 26 min to burn
Type III-IV
🟡 39 min to burn
Type V-VI
🟢 65 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
20°C
Humid/Sticky
Heat Stress
Low
No heat warning
🙂 Best outdoor time:
Morning hours (before 11 AM)
Marine Conditions
Marine Life
No special warnings. Enjoy the swim!
Swim Index
✅ Excellent Swimming Conditions
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in Italy
Flight Traffic
High
97/100 pressure index
Health Advisory
Required
1 vaccine • View Details →
Landing Slots
~144
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Naples
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
05:50
☀️ Noon
11:57
🌇 Sunset
18:04
⏱️ Daylight
12h 14m
Wind Speed
14.5 km/h
Gentle breeze
Sunshine
9.8 hrs
Direct Sun (Cloud-free)
Humidity
73%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Naples
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 Naples
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.
Volcanic Activity
Nearest: Mount Vesuvius
13.8km away
Travel Alert: This region has elevated natural risks. We recommend registering with your embassy and keeping emergency numbers handy.
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Naples on September 21 averages 25.2°C with a 24% precipitation probability. Wedding/Outdoor Event Score: 97/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Naples Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Better Alternatives Nearby
Consider these dates within ±7 days
September 14
26.3°C • 19% rain
Score
99
September 15
26.1°C • 23% rain
Score
98
September 16
25.8°C • 23% rain
Score
98
💡 Moving your event by a few days could significantly improve weather conditions
Compare Other Cities
Same date (September 21) in other destinations
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🌍 Explore the same date in different destinations around the world
📍 Is Naples Worth Visiting on September 21?
Planning a trip to Naples on September 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 25.2°C with a 24% historical precipitation risk.
✈️ Travel Logistics: Approximately 144 landing slots available daily during this period, indicating manageable crowd levels.
💉 Health Advisory: 7 vaccinations are recommended for Italy, including COVID-19.
🌊 Coastal Conditions: Water temperature averages 24.9°C (swimming pool). Wave conditions are generally lake-like with heights around 0.4m.
📊 Historical Extremes: The hottest September 21 recorded in the last 30 years saw temperatures hit 30.5°C in 2023, while the coldest dropped to 10.4°C in 2017.