September 20 is generally a great time to visit San Antonio. While there is a slight chance of rain (16%), showers are usually brief. Expect comfortable 33°C weather. San Antonio is currently in its most popular travel window, meaning vibrant crowds and premium pricing.
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Essential Travel Info for San Antonio
Currency
USD
$ United States dollar
Language
English
Driving
Right side
Connect
As of Dec 2021, San Antonio has 5G from ...
Safety
Moderate Safety
GPI: 2.44
San Antonio Weather Forecast for September 20
"Warm & Sunny. Expect average highs of 32.5°C. 16% chance of rain."
What to Wear in San Antonio in September
Based on historical data for September 20, San Antonio typically experiences temperatures between 22.7°C and 32.5°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 San Antonio
Smart Suitcase
- T-Shirt
- Light Clothing
Average High
32.5°C
Daytime Peak
Average Low
22.7°C
Nighttime Low
Feels Like
40.4°C
🔥 Heat index effect
Rain Chance
16%
Avg 1.4mm if it rains
Cloud Cover
41%
Light drizzle
Pressure
1013.7 hPa
Low volatility
San Antonio 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
07:00 - 10:00
16:00 - 19:00
Type I-II
🔴 21 min to burn
Type III-IV
🟡 32 min to burn
Type V-VI
🟢 53 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
25.3°C
Humid/Sticky
Heat Index
40.4°C
Feels hotter
😐 Best outdoor time:
Early morning (6-9 AM) or evening (after 6 PM)
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in United States
Flight Traffic
High
83/100 pressure index
Health Advisory
Healthy
Routine only • View Details →
Landing Slots
~135
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in San Antonio
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
07:22
☀️ Noon
13:28
🌇 Sunset
19:34
⏱️ Daylight
12h 12m
Wind Speed
15.9 km/h
Gentle breeze
Sunshine
10.2 hrs
Direct Sun (Cloud-free)
Humidity
66%
Slightly humid
Travel Intelligence
Exclusive flight analytics & health data for San Antonio
Smart Flight Estimator
Airport-to-Airport Logistics
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Travel Health & Safety in San Antonio
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 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, San Antonio on September 20 averages 32.5°C with a 16% precipitation probability. Wedding/Outdoor Event Score: 97/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
San Antonio Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Better Alternatives Nearby
Consider these dates within ±7 days
September 21
32.3°C • 15% rain
Score
100
September 22
32.2°C • 13% rain
Score
100
September 23
32.1°C • 12% rain
Score
100
💡 Moving your event by a few days could significantly improve weather conditions
Compare Other Cities
Same date (September 20) in other destinations
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🌍 Explore the same date in different destinations around the world
📍 Is San Antonio Worth Visiting on September 20?
Planning a trip to San Antonio on September 20? Our historical weather analysis based on 30 years of NASA satellite data shows that this time of year typically offers vibrant summer conditions averaging 32.5°C with a 16% historical precipitation risk.
✈️ Travel Logistics: Approximately 135 landing slots available daily during this period, indicating manageable crowd levels.
📊 Historical Extremes: The hottest September 20 recorded in the last 30 years saw temperatures hit 36.7°C in 2021, while the coldest dropped to 18.1°C in 2020.