September 21 is statistically one of the best days of the year in Prague. With minimal rain risk (11%) and pleasant highs of 19°C, it's ideal for outdoor adventures. As it's peak season for Prague, we recommend booking your stay well in advance to secure the best rates.
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Essential Travel Info for Prague
Currency
CZK
Kč Czech koruna
Language
Czech
+1 more
Driving
Right side
Connect
Prague has 5G from all Czech carriers (O...
Safety
Very High Safety
GPI: 1.318
Prague Weather Forecast for September 21
"Mild & Comfortable. Expect average highs of 18.9°C. 11% chance of rain."
What to Wear in Prague in September
Based on historical data for September 21, Prague typically experiences temperatures between 9.5°C and 18.9°C. We recommend packing light jacket, long pants to stay comfortable. Trends suggest it will stay mostly dry (11% rain probability), but checking the forecast before heading out is always wise.
Complete Packing Guide
Weekly breakdown & essential items for Prague
Smart Suitcase
- Light Jacket
- Long Pants
Average High
18.9°C
Daytime Peak
Average Low
9.5°C
Nighttime Low
Feels Like
18.9°C
🌤️ Feels accurate
Rain Chance
11%
Avg 0.6mm if it rains
Cloud Cover
56%
Overcast
Pressure
1018.2 hPa
Medium volatility
Prague Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
✓ Weather is generally predictable, but pack for minor variations. A light backup layer is recommended.
Sun Exposure
UV Index & Safety Guide
Protection Needed
SPF 15 for extended outdoor time
Type I-II
🔴 33 min to burn
Type III-IV
🟡 50 min to burn
Type V-VI
🟢 83 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
13.7°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 Czech Republic
Flight Traffic
High
100/100 pressure index
Health Advisory
Healthy
Routine only • View Details →
Landing Slots
~336
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Prague
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
05:47
☀️ Noon
11:56
🌇 Sunset
18:05
⏱️ Daylight
12h 17m
Wind Speed
13.4 km/h
Gentle breeze
Sunshine
8.0 hrs
Direct Sun (Cloud-free)
Humidity
72%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Prague
Smart Flight Estimator
Airport-to-Airport Logistics
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Travel Health & Safety in Prague
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 acceptable. Sensitive individuals should limit prolonged outdoor exertion.
Regional Safety Profile
Seismic Activity
Zero seismic activity detected in 30 years.
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Prague on September 21 averages 18.9°C with a 11% precipitation probability. Wedding/Outdoor Event Score: 100/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Prague Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Compare Other Cities
Same date (September 21) in other destinations
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📍 Is Prague Worth Visiting on September 21?
Planning a trip to Prague on September 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 18.9°C with a 11% historical precipitation risk.
✈️ Travel Logistics: Approximately 336 landing slots available daily during this period, indicating manageable crowd levels.
📊 Historical Extremes: The hottest September 21 recorded in the last 30 years saw temperatures hit 29.6°C in 2018, while the coldest dropped to 4.2°C in 2019.