April 21 is generally a great time to visit San Antonio. While there is a slight chance of rain (24%), showers are usually brief. Expect comfortable 27°C weather. As it's peak season for San Antonio, we recommend booking your stay well in advance to secure the best rates.
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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 April 21
"Warm & Sunny. Expect average highs of 27.4°C. 24% chance of rain."
What to Wear in San Antonio in April
Based on historical data for April 21, San Antonio typically experiences temperatures between 16.8°C and 27.4°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 San Antonio
Smart Suitcase
- T-Shirt
- Light Clothing
Average High
27.4°C
Daytime Peak
Average Low
16.8°C
Nighttime Low
Feels Like
29.4°C
🔥 Minor difference
Rain Chance
24%
Avg 1.1mm if it rains
Cloud Cover
59%
Light drizzle
Pressure
1014 hPa
Medium 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 94% 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 - 20:00
Type I-II
🔴 17 min to burn
Type III-IV
🟡 26 min to burn
Type V-VI
🟢 43 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
21.2°C
Humid/Sticky
Heat Index
29.4°C
Feels hotter
🙂 Best outdoor time:
Any time during daylight hours
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in United States
Flight Traffic
High
97/100 pressure index
Health Advisory
Healthy
Routine only • View Details →
Landing Slots
~158
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in San Antonio
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
07:02
☀️ Noon
13:33
🌇 Sunset
20:05
⏱️ Daylight
13h 2m
Wind Speed
20.4 km/h
Moderate wind
Sunshine
8.5 hrs
Direct Sun (Cloud-free)
Humidity
69%
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
💰💰 Moderate
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, San Antonio on April 21 averages 27.4°C with a 24% 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
April 14
27.1°C • 17% rain
Score
99
April 15
27°C • 16% rain
Score
99
April 16
26.9°C • 17% rain
Score
98
💡 Moving your event by a few days could significantly improve weather conditions
Compare Other Cities
Same date (April 21) in other destinations
🌍 Explore the same date in different destinations around the world
📍 Is San Antonio Worth Visiting on April 21?
Planning a trip to San Antonio on April 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 27.4°C with a 24% historical precipitation risk.
✈️ Travel Logistics: Approximately 158 landing slots available daily during this period, indicating manageable crowd levels.
📊 Historical Extremes: The hottest April 21 recorded in the last 30 years saw temperatures hit 29.9°C in 2020, while the coldest dropped to 8.2°C in 2021.