March 18 is generally a great time to visit San Francisco. While there is a slight chance of rain (20%), showers are usually brief. Expect comfortable 16°C weather. Take advantage of the off-peak calm in San Francisco to see the sights without the usual crowds.
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Essential Travel Info for San Francisco
Currency
USD
$ United States dollar
Language
English
Driving
Right side
Connect
Thearea codesfor San Francisco are 415 a...
Safety
Moderate Safety
GPI: 2.44
San Francisco Weather Forecast for March 18
"Mild & Comfortable. Expect average highs of 15.5°C. 20% chance of rain."
What to Wear in San Francisco in March
Based on historical data for March 18, San Francisco typically experiences temperatures between 8.6°C and 15.5°C. We recommend packing light jacket, long pants to stay comfortable. Trends suggest it will stay mostly dry (20% rain probability), but checking the forecast before heading out is always wise.
Complete Packing Guide
Weekly breakdown & essential items for San Francisco
Smart Suitcase
- Light Jacket
- Long Pants
Average High
15.5°C
Daytime Peak
Average Low
8.6°C
Nighttime Low
Feels Like
15.5°C
🌤️ Feels accurate
Rain Chance
20%
Avg 1.1mm if it rains
Cloud Cover
59%
Overcast
Pressure
1017.6 hPa
Medium volatility
San Francisco Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 98% of the time. Safe to plan outdoor activities with confidence.
Sun Exposure
UV Index & Safety Guide
Protection Needed
SPF 15 for extended outdoor time
Type I-II
🔴 29 min to burn
Type III-IV
🟡 44 min to burn
Type V-VI
🟢 73 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
12.1°C
Pleasant
Heat Stress
Low
No heat warning
🙂 Best outdoor time:
Any time during daylight hours
Marine Conditions
Marine Life
No special warnings. Enjoy the swim!
Swim Index
❄️ Cold Water Hazard
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in United States
Flight Traffic
Quiet
26/100 pressure index
Health Advisory
Healthy
Routine only • View Details →
Landing Slots
~563
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in San Francisco
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
06:17
☀️ Noon
12:19
🌇 Sunset
18:20
⏱️ Daylight
12h 2m
Wind Speed
21.2 km/h
Moderate wind
Sunshine
9.1 hrs
Direct Sun (Cloud-free)
Humidity
80%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for San Francisco
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 Francisco
Travel Comfort Index
Real-time tourism conditions
Weather Quality
☀️ Excellent
Tourist Crowds
🟢 Moderate
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
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 Francisco on March 18 averages 15.5°C with a 20% precipitation probability. Wedding/Outdoor Event Score: 86/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
San Francisco Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Compare Other Cities
Same date (March 18) in other destinations
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📍 Is San Francisco Worth Visiting on March 18?
Planning a trip to San Francisco on March 18? 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 15.5°C with a 20% historical precipitation risk.
✈️ Travel Logistics: Approximately 563 landing slots available daily during this period, indicating peak tourist activity.
🌊 Coastal Conditions: Water temperature averages 12.6°C (polar plunge). Wave conditions are generally surfers only with heights around 1.47m.
📊 Historical Extremes: The hottest March 18 recorded in the last 30 years saw temperatures hit 19.2°C in 2019, while the coldest dropped to 6.1°C in 2025.