Question 1

What is the annual temperature range in San Francisco?

Accepted Answer

San Francisco has one of the mildest, most stable annual temperature ranges of any major U.S. city, with monthly average temperatures spanning just 7.5°C (13.5°F) across all of 2025. The coldest month was January, averaging 10.1°C (50.2°F), while the warmest was September at 17.6°C (63.7°F).

Across the full 2025 calendar year, San Francisco's overall mean temperature was 13.5°C (56.3°F). Typical daily highs averaged 24.6°C (76.2°F) and typical daily lows averaged 6.8°C (44.2°F).

Even the year's extremes stayed moderate by big-city standards:

- **Hottest peak:** 33.6°C (92.5°F), recorded in September 2025
- **Coldest low:** 2.8°C (37.0°F), recorded in March 2025
- **Warmest-to-coldest monthly swing:** only 7.5°C (13.5°F)

This compressed temperature range is the hallmark of San Francisco's coastal Mediterranean climate, where the cool Pacific Ocean moderates conditions year-round. For visitors, it means there's no true "hot" or "cold" season to plan around — layered clothing works in nearly every month, since a mild afternoon can quickly turn breezy and cool once coastal air moves in.

Question 2

Which season is the wettest in San Francisco?

Accepted Answer

Winter is by far the wettest season in San Francisco, when the city receives the vast majority of its annual rainfall. San Francisco has a Mediterranean climate, meaning rain is heavily concentrated in the cooler months while summers stay almost completely dry.

In 2025, the meteorological winter months of January and February delivered 139.3 mm (5.48 in) of rain — more than any other season. December 2025, which begins the next winter (Winter 2025/26), added another 115.4 mm (4.54 in). February 2025 was the single wettest month at 129.1 mm (5.08 in).

By contrast, the other seasons in San Francisco were much drier:

- **Spring (March–May):** 65.7 mm (2.59 in)
- **Autumn (September–November):** 106.1 mm (4.18 in)
- **Summer (June–August):** just 0.8 mm (0.03 in)

Summer was effectively rainless, with June and July recording 0.0 mm combined. Across all of 2025, San Francisco totaled 427.3 mm (16.8 in) of precipitation, with average humidity around 81%.

For visitors, this pattern means winter (December to February) is the time to pack a rain jacket and an umbrella, while late spring through early autumn offers reliably dry, outdoor-friendly weather. If you want to avoid rain in San Francisco, plan your trip between May and September, when measurable precipitation is rare.

Question 3

What is the sunniest time of year in San Francisco?

Accepted Answer

The sunniest time of year in San Francisco is late spring through summer, with the peak running from May to August 2025. During these four months the city recorded a combined 1,523 sunshine hours, averaging about 381 hours of sun per month.

May 2025 was the single brightest month of the year with 396.7 sunshine hours (roughly 12.8 hours of sun per day), narrowly ahead of July at 390.7 hours and August at 390.6 hours. Across the meteorological summer (June–August 2025), San Francisco totaled 1,126 sunshine hours, far more than autumn's 722 hours or winter's 554 hours (January, February and December).

This sunny stretch is also remarkably dry: from May through August 2025, San Francisco saw just 2.7 mm (0.11 in) of total rainfall, while average temperatures stayed mild at around 15.1°C (59.1°F). Skies dimmed most in late autumn and winter, with February the cloudiest month at only 158.7 sunshine hours.

For visitors, this means the best window for sun-dependent plans in San Francisco is roughly May to August, when long, dry days favor sightseeing, walking the waterfront, and outdoor dining. Keep in mind that the city's famous coastal fog can still trim morning sunshine even during these brightest months, so afternoons tend to be the most reliably clear.

Question 4

What is the weather like in San Francisco in July?

Accepted Answer

San Francisco stays surprisingly cool and dry in July, with mild temperatures, persistent ocean fog, and a steady afternoon breeze rather than the hot summer many visitors expect.

In July 2025, San Francisco recorded an average temperature of 15.1°C (59.1°F), with daily highs averaging just 18.2°C (64.7°F) and overnight lows around 12.4°C (54.3°F). The month was remarkably stable: the warmest reading reached only 21.0°C (69.8°F), and on 29 of 31 days the high stayed below 20°C (68°F). Not a single drop of rain fell, with total precipitation of 0.0 mm across the whole month.

Two other factors define a San Francisco July. Humidity averaged a high 85.1%, reflecting the marine layer and morning fog that roll in off the Pacific. Winds were consistently brisk, averaging 19.6 km/h (12.2 mph) and gusting up to 28.1 km/h (17.5 mph), which makes the air feel cooler than the thermometer suggests.

For travelers, this means July is reliably rain-free and comfortable for sightseeing, but it is not beach-and-sunbathing weather. Pack layers and a light jacket or windbreaker, since cool mornings and a chilly evening breeze are the norm even in mid-summer. If you want warmer conditions in San Francisco, September and October typically bring the city's mildest, fog-free days.

Question 5

When is San Francisco the windiest, and which months are calmest?

Accepted Answer

San Francisco is windiest in late spring and summer, with June 2025 being the breeziest month at an average wind speed of 21.3 km/h (13.2 mph). The calmest stretch falls in winter, when January 2025 averaged just 8.3 km/h (5.2 mph).

Across the full 2025 calendar year, San Francisco averaged 14.8 km/h (9.2 mph). The seasonal contrast is striking: the windiest month (June) was roughly 2.6 times breezier than the calmest (January). Winds build steadily through spring and stay elevated all summer, with the May–August window averaging 20.1 km/h (12.5 mph).

Key 2025 monthly wind averages:

- **June:** 21.3 km/h (13.2 mph) — the windiest month
- **May:** 20.9 km/h (13.0 mph)
- **July:** 19.6 km/h (12.2 mph)
- **January:** 8.3 km/h (5.2 mph) — the calmest month
- **November:** 10.8 km/h (6.7 mph)

This pattern reflects San Francisco's classic summer sea breeze, when cool ocean air rushes through the bay to replace warm inland air. For visitors, it means packing a windproof layer for summer afternoons, even on sunny days. If you prefer calmer conditions for sightseeing, sailing, or photography, the late autumn and winter months of October through January typically deliver the gentlest winds of the year in San Francisco.

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FAQ

What is the annual temperature range in San Francisco?

Which season is the wettest in San Francisco?

What is the sunniest time of year in San Francisco?

What is the weather like in San Francisco in July?

When is San Francisco the windiest, and which months are calmest?