Best Time to Visit San Francisco

Photo by Thomas Haas on Unsplash

September and October are the best months, and it isn't close. September runs a high of 21.3°C (70.3°F) with lows of 15.4°C (59.7°F) and just 8.3mm (0.33in) of rain across 2 days; October holds 20.4°C (68.7°F) with 37.8mm (1.5in) over 4 days. Those are the two warmest months of the San Francisco year — warmer than July, which tops out at 17.2°C (63.0°F) — and they land after the summer fog has burned off but before the winter rain starts in earnest.

September and October: the actual summer

San Francisco's warmest month is September, not July. The 2025 measurements make that plain: September high 21.3°C (70.3°F), July high 17.2°C (63.0°F). A 4.1°C (7.4°F) gap between them is enormous in a city whose entire annual high range is only 8°C (14.4°F) wide.

What 21.3°C (70.3°F) means on the ground: shirtsleeves from about 11am to 6pm, no sweating on hills, and comfortable standing around outdoors. What the 15.4°C (59.7°F) low means: you still want a layer after sunset. The daily spread in September is only 5.9°C (10.6°F), so evenings don't crash the way they do in a desert city — but 15.4°C (59.7°F) with wind coming off the water reads colder than the number looks, especially near Ocean Beach, the Presidio, or on a boat to Alcatraz.

The rain figure is the other half of the case. September's 8.3mm (0.33in) fell over 2 days. That is not "a rainy season with breaks" — that is two brief events across an entire month and 28 dry days. October's 37.8mm (1.5in) over 4 days is still a functionally dry month: you plan nothing around it, you just carry a shell.

August deserves a mention alongside them. High 20.1°C (68.2°F), low 13.9°C (57.0°F), and 0.3mm (0.01in) of rain across 0 measurable rain days. Warm, effectively rainless, and only 1.2°C (2.2°F) cooler than September. August through October is a three-month window where the weather is a non-issue.

Months to avoid: December through March

The wet season is real and it is concentrated. February took 140.6mm (5.5in) across 11 days. December took 127.5mm (5.0in) across 10 days. March took 91.7mm (3.6in) across 12 days — the highest rain-day count of the year.

Do the arithmetic on March: 91.7mm spread over 12 days averages 7.6mm (0.3in) per rainy day. That is grey, steady, all-day drizzle across nearly half the month, not brief downpours you wait out under an awning. February is the opposite pattern — 140.6mm across 11 days averages 12.8mm (0.5in) per rainy day, which is heavier, genuinely wet weather that soaks shoes and shuts down outdoor plans.

Temperature is the second problem. December's high is 13.3°C (55.9°F), the coldest month of the year, with lows of 8.3°C (46.9°F). February holds 14.8°C (58.6°F) / 8.1°C (46.6°F). Nothing freezes and nothing snows, but 13.3°C (55.9°F) in the rain with wind is the specific kind of cold that ruins a walking day.

January 2025 was the odd one out: 24.2mm (0.95in) over just 2 days, with a high of 14.9°C (58.8°F). That is a dry January by San Francisco standards — this is a single year of measurement, and January is normally a core wet month. Treat that number as one year's luck rather than a reason to book.

The other thing to avoid: June and July fog

This is the part visitors get wrong. June and July are not hot, and they are not even warm. June's high is 17.7°C (63.9°F), July's is 17.2°C (63.0°F) — meaning July is only 0.3°C (0.5°F) warmer than April's 16.9°C (62.4°F), and both are cooler than May's 19.0°C (66.2°F). Summer in San Francisco is a dip in the temperature curve, not a peak.

The rain numbers explain why: June 0.0mm (0in) over 0 days, July 1.0mm (0.04in) over 0 days. It is not raining. It is the marine layer — coastal fog that sits over the western half of the city, blocks the sun for most of the morning, and keeps highs pinned in the 17°C (63°F) range while inland California bakes. Dry, grey, and windy.

If your trip is fixed to July, it is still a fine trip; you just need to pack for 17.2°C (63.0°F) and 12.8°C (55.0°F) — jacket weather, all day, in midsummer. The mistake is packing for the word "July" instead of the number.

Shoulder season: April, May, and November

May is the best-value month by a distance. High 19.0°C (66.2°F), low 11.5°C (52.7°F), and 4.1mm (0.16in) of rain over a single day. That is warmer than any month from June through July, essentially dry, and it sits before the summer crowd arrives. May is the one month where good weather and lower prices genuinely overlap.

April works too: 16.9°C (62.4°F) / 10.2°C (50.4°F) with 10.0mm (0.4in) over 3 days. Cooler and slightly damp, but three rain days in a month is background noise. April is a light-jacket trip with full access to everything outdoors.

November is the gamble. High 16.5°C (61.7°F) is perfectly workable, but 87.8mm (3.5in) across 9 days means roughly one day in three is wet, and the rain is heavy when it comes — 9.8mm (0.4in) per rainy day. Early November often still behaves like October; late November behaves like December. If you go, price it as a wet-season trip and treat any dry stretch as a bonus.

What each season actually means for you

Late summer and autumn (Aug–Oct). Highs 20.1–21.3°C (68.2–70.3°F), lows 13.5–15.4°C (56.3–59.7°F), rain from 0.3mm to 37.8mm. You will walk 15,000+ steps a day without weather interfering. Wear a t-shirt with a mid-weight layer in a daypack for the evening drop and the wind on the bridge. No umbrella needed in August or September; a packable shell for October.

Winter (Dec–Mar). Highs 13.3–15.3°C (55.9–59.5°F), 10–12 rain days a month. You will be building the trip around indoor anchors — museums, the Ferry Building, restaurants — with walking slotted into dry windows. A waterproof jacket beats an umbrella here because the wind will destroy the umbrella. Waterproof shoes matter more than a heavy coat; 13.3°C (55.9°F) is not cold enough to need serious insulation.

Spring (Apr–May). Highs 16.9–19.0°C (62.4–66.2°F), 1–3 rain days. Full outdoor access with a layer you take on and off. Golden Gate Park, Twin Peaks, and coastal walks all work.

Fog season (Jun–Jul). Highs 17.2–17.7°C (63.0–63.9°F), lows 11.8–12.8°C (53.2–55.0°F), zero rain days. You will be in a jacket most of the day and glad of it near the coast. Mornings are grey; afternoons often clear on the eastern side of the city (Mission, Dogpatch) while the west stays socked in. Plan bridge and viewpoint visits for mid-afternoon.

Month-by-month

• January — 14.9°C / 7.3°C (58.8°F / 45.1°F), 24.2mm (0.95in) over 2 days. Unusually dry in 2025; don't count on a repeat.
• February — 14.8°C / 8.1°C (58.6°F / 46.6°F), 140.6mm (5.5in) over 11 days. Wettest month of the year. Skip it.
• March — 15.3°C / 8.9°C (59.5°F / 48.0°F), 91.7mm (3.6in) over 12 days. Most rain days of any month — grey and persistent.
• April — 16.9°C / 10.2°C (62.4°F / 50.4°F), 10.0mm (0.4in) over 3 days. Rain season breaks. Good, quiet, cheap.
• May — 19.0°C / 11.5°C (66.2°F / 52.7°F), 4.1mm (0.16in) over 1 day. Best shoulder month; warmer than June or July.
• June — 17.7°C / 11.8°C (63.9°F / 53.2°F), 0.0mm over 0 days. Dry but foggy and cool.
• July — 17.2°C / 12.8°C (63.0°F / 55.0°F), 1.0mm (0.04in) over 0 days. Coolest daytime highs of the summer.
• August — 20.1°C / 13.9°C (68.2°F / 57.0°F), 0.3mm (0.01in) over 0 days. Fog lifts, warmth arrives.
• September — 21.3°C / 15.4°C (70.3°F / 59.7°F), 8.3mm (0.33in) over 2 days. Warmest month. The best time to go.
• October — 20.4°C / 13.5°C (68.7°F / 56.3°F), 37.8mm (1.5in) over 4 days. Nearly as good, slightly wetter.
• November — 16.5°C / 11.1°C (61.7°F / 52.0°F), 87.8mm (3.5in) over 9 days. Rain season restarts.
• December — 13.3°C / 8.3°C (55.9°F / 46.9°F), 127.5mm (5.0in) over 10 days. Coldest and second-wettest.

FAQ

Is San Francisco really cold in summer?

Cool rather than cold, but yes — colder than most visitors expect. July's high is 17.2°C (63.0°F) and its low is 12.8°C (55.0°F). That is 4.1°C (7.4°F) cooler at midday than September. You need a jacket in July, and you'll wear it more hours than you expect near the coast.

What is the driest time to visit?

June through August. June recorded 0.0mm of rain over 0 days, July 1.0mm (0.04in) over 0 days, and August 0.3mm (0.01in) over 0 days. September follows closely at 8.3mm (0.33in) over 2 days — and September is 4.1°C (7.4°F) warmer than July, which makes it the better pick if you want dry *and* warm.

How bad is the rain in winter, really?

Bad enough to reshape a trip. February delivers 140.6mm (5.5in) across 11 days and December 127.5mm (5.0in) across 10 days — roughly one wet day in three, and the per-day totals (12.8mm and 12.8mm respectively) mean real rain, not a passing shower. March has the most rain days of all at 12, though the total is lower at 91.7mm (3.6in), which reads as prolonged drizzle rather than downpours.

Do I need a heavy coat at any point?

No. The coldest month, December, still has a high of 13.3°C (55.9°F) and a low of 8.3°C (46.9°F) — a fleece or sweater under a waterproof shell handles the entire winter. What you actually need is wind and water protection, plus shoes with grip: the hills plus wet pavement are the real hazard, not the temperature. In September and October, a single mid-layer for the 15.4°C (59.7°F) and 13.5°C (56.3°F) evenings is enough.

Climate figures are 2025 measured values for San Francisco. One year of data shows the shape of the year clearly, but individual months vary — January 2025 in particular was drier than a typical January. Check a forecast close to your travel dates.