San Francisco Weather in May
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Updated: March 2026
Is May a Good Time to Visit San Francisco?
May is a excellent time to visit San Francisco (8/10). With 13 daily sunshine hours and only 3 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 2nd sunniest of the year in San Francisco. Beach and outdoor-focused visitors will find May ideal, though hotel prices reflect demand and popular sites get crowded by mid-morning. April offers a similar profile at lower hotel rates if dates are flexible. The main practical note: San Francisco's popular sites are busiest between 10am and 3pm regardless of season. Arriving at opening time or after 4pm makes a significant difference to the experience. Planning tips: book accommodation at least 6-8 weeks ahead, as popular hotels fill quickly during May. Purchasing skip-the-line tickets for major attractions in advance saves meaningful time. If you have flexibility, arriving a few days before or after peak weekends reduces both crowds and prices noticeably.
The single most important thing to know about visiting San Francisco in May: conditions are genuinely cooperative, with 19°C highs and only 3 wet days making this one of the more straightforward months to plan around. Precipitation totals 18mm for the month, spread across roughly 3 days, and 13 sunshine hours per day give you a reliable window for outdoor plans.
19°C
Avg High
11°C
Avg Low
3 days
Rain Days
13h
Sunshine
65%
Humidity
Temperature in San Francisco in May
The 8°C day-night temperature range is typical for continental climates: a light jacket in the morning that you shed by midday and need again after sunset. Humidity averages 65%, which is comfortable for most visitors. On warmer days, lighter fabrics help with the mild stickiness in the afternoon. UV index averages 9 this month, classed as high to very high. SPF 30+ sunscreen, a brim hat, and sunglasses are not optional between 10am and 4pm. Wind averages 21 km/h, light enough to be refreshing on warm days but noticeable in open coastal areas or elevated viewpoints. In Fahrenheit: 66°F average high, 52°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Temperature in May
Monthly Precipitation (mm)
What to Wear in San Francisco in May
Packing for San Francisco in May means dressing for 19°C days and 11°C evenings. A light cotton tee with a casual overshirt works well at 19°C, the overshirt doubles as a layer for air-conditioned venues. Evening temperatures settle at 11°C, a modest 8°C drop that a light cardigan or denim jacket covers. Comfortable walking trainers are the versatile choice for both outdoor sightseeing and indoor venues.
Local tip: Layers are more practical than a single heavy garment in San Francisco. The day-to-evening temperature shift rewards packing a versatile mid-layer you can add or remove as conditions change.
Events in San Francisco in May
May has no major festivals or public holidays in San Francisco, which is one of its practical advantages for independent travellers. Attractions run at lower capacity than during peak event periods, queues are shorter, and accommodation is easier to find without needing to book many months in advance. Local restaurants, markets, and transport operate at a relaxed pace, making this an ideal time for visitors who prefer a more authentic, unhurried experience of everyday city life rather than large crowds drawn in by a single major headline event.
What to Pack for San Francisco in May
Based on 19°C average highs and 3 rainy days
- Light jacket or cardigan for cooler evenings
- Mix of short and long-sleeve layers
- Comfortable walking shoes with good arch support
- Universal travel adapter
- Small day pack for city exploration
- Reusable water bottle
Best Activities in San Francisco in May
- Explore outdoor markets and street food stallsMid-morning (10am-12pm)At 19°C, the temperature is ideal for extended walking without overheating
- Guided walking tour of the historic centreMorning or late afternoonComfortable temperatures allow several hours on foot without fatigue
- Visit rooftop viewpoints and observation decksGolden hour (1 hour before sunset)Warm clear evenings provide exceptional visibility for panoramic photography
- Day trip to the surrounding countryside or coastFull day (depart by 8am)May is reliably dry enough for rural day trips without weather risk
- Afternoon in a world-class museum or galleryAfternoon (2-5pm)Pairs well with outdoor morning activities and provides a mid-day rest from sightseeing
- Coffee-house or traditional cafe culture experienceMid-morning or post-lunchA cultural ritual in this region that rewards slow appreciation regardless of weather
- Evening live music, theatre, or opera performanceEvening shows typically at 7-9pmConsistent evening temperatures make getting to and from evening venues comfortable
- Visit the main botanical garden or city park at seasonal peakYear-round; best light in morningMay brings distinct seasonal changes to public green spaces worth exploring
- Try the seasonal farmer's market for local produce and street foodSaturday morning markets typically 8am-1pmMay seasonal produce is at peak availability, offering dishes not found at other times of year
Why is San Francisco mild in May?
May marks the transition into warmer conditions in San Francisco, as the sun angle climbs and day length extends. Temperatures averaging 19°C by day and 11°C overnight reflect a city shaking off winter: the morning air still carries a cool edge, but afternoons are noticeably warmer than even four weeks prior. At 38 degrees north latitude, spring is one of the most dynamic periods in the annual cycle, with weekly temperature changes that can be larger than the month-to-month shifts of summer. This volatility is part of the appeal: San Francisco in May has a freshness and energy that peak-summer heat tends to mute. Layers remain essential, but there are reliable pockets of warmth that reward patience. Climate data: Open-Meteo ERA5 (1991–2020).
Sunshine Hours
The average number of hours per day with direct sunlight. Calculated from satellite measurements. Days with more than 7 hours of sunshine are ideal for outdoor activities. Under 3 hours means overcast conditions dominate.
UV Index
A scale from 0-11+ measuring ultraviolet radiation intensity. UV 0-2: Minimal risk. UV 3-5: Moderate -- wear sunscreen. UV 6-7: High -- hat and SPF 30+ essential. UV 8-10: Very High -- limit midday exposure. UV 11+: Extreme -- seek shade between 10am-4pm.
Rain Days
A rain day is counted when precipitation exceeds 0.1mm. This threshold captures even light drizzle. Unlike total rainfall in mm, rain days tells you how often you might need an umbrella, which is useful for planning outdoor activities.
Humidity
Relative humidity as a percentage. Below 40%: Dry -- skin and throat may feel parched. 40-60%: Comfortable -- ideal for most people. 60-80%: Sticky -- light, breathable fabrics recommended. Above 80%: Muggy -- heat feels more intense; quick-dry clothing is essential.
Frequently Asked Questions: San Francisco in May
May ranks 2nd sunniest of the year in San Francisco, with an average 13 daily sunshine hours. The driest months are July, August, and September. September is the hottest month (23°C avg high); January is the coolest (14°C). From here, temperatures rise 2°C into June. Compared to last month (April: 17°C high, 5 rain days), May is warmer and drier. May is among the top three sunniest months to visit San Francisco.
Year-Round Climate
Plan Your Trip to San Francisco
Data Sources for San Francisco
Climate normals represent 30-year averages (1991-2020). Individual years may vary.