August 18 is statistically one of the best days of the year in San Diego. With minimal rain risk (2%) and pleasant highs of 25°C, it's ideal for outdoor adventures. As it's peak season for San Diego, we recommend booking your stay well in advance to secure the best rates.
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Essential Travel Info for San Diego
Currency
USD
$ United States dollar
Language
English
Driving
Right side
Connect
The most common area code for San Diego ...
Safety
Moderate Safety
GPI: 2.44
San Diego Weather Forecast for August 18
"Warm & Sunny. Expect average highs of 25.2°C. 2% chance of rain."
What to Wear in San Diego in August
Based on historical data for August 18, San Diego typically experiences temperatures between 18.3°C and 25.2°C. We recommend packing t-shirt, light clothing to stay comfortable. Trends suggest it will stay mostly dry (2% rain probability), but checking the forecast before heading out is always wise.
Complete Packing Guide
Weekly breakdown & essential items for San Diego
Smart Suitcase
- T-Shirt
- Light Clothing
Average High
25.2°C
Daytime Peak
Average Low
18.3°C
Nighttime Low
Feels Like
26.1°C
☀️ Feels accurate
Rain Chance
2%
Avg 0mm if it rains
Cloud Cover
27%
Overcast
Pressure
1012.4 hPa
Low volatility
San Diego Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 100% of the time. Safe to plan outdoor activities with confidence.
Sun Exposure
UV Index & Safety Guide
Protection Needed
SPF 30+ required, seek shade
05:00 - 10:00
16:00 - 18:00
Type I-II
🔴 13 min to burn
Type III-IV
🟡 20 min to burn
Type V-VI
🟢 33 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
21.1°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 United States
Flight Traffic
High
80/100 pressure index
Health Advisory
Healthy
Routine only • View Details →
Landing Slots
~357
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in San Diego
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
05:15
☀️ Noon
11:53
🌇 Sunset
18:32
⏱️ Daylight
13h 16m
Wind Speed
15.2 km/h
Gentle breeze
Sunshine
11.4 hrs
Direct Sun (Cloud-free)
Humidity
78%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for San Diego
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 San Diego
Travel Comfort Index
Real-time tourism conditions
Weather Quality
☀️ Excellent
Tourist Crowds
🔴 Very Busy
Price Level
💰💰💰 Expensive
Health & Wellbeing
Meteo-Health Forecast
Stable conditions. Low risk of headaches.
Mild discomfort possible for arthritic conditions.
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.
Eastern Pacific Hurricane Risk
Season: May - Nov
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, San Diego on August 18 averages 25.2°C with a 2% precipitation probability. Wedding/Outdoor Event Score: 100/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
San Diego Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Compare Other Cities
Same date (August 18) in other destinations
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📍 Is San Diego Worth Visiting on August 18?
Planning a trip to San Diego on August 18? 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 2% historical precipitation risk.
✈️ Travel Logistics: Approximately 357 landing slots available daily during this period, indicating manageable crowd levels.
🌊 Coastal Conditions: Water temperature averages 22°C (swimming pool). Wave conditions are generally fun waves with heights around 0.81m.
📊 Historical Extremes: The hottest August 18 recorded in the last 30 years saw temperatures hit 30.1°C in 2020, while the coldest dropped to 16.4°C in 2025.