San Francisco in September
In September, San Francisco averages 24°C (75°F) during the day and 14°C (57°F) at night, with only about 2 rainy days.
ShoulderConditions are comfortable for sightseeing without being sweltering. Skies are generally dry and clear.
It's peak hurricane season in San Francisco during September. Travel is possible but expect storm risk, possible flight disruption, and generally lower travel insurance coverage.
How September compares to the rest of the year in San Francisco
September is one of the warmest months in San Francisco (1st of 12) and moderately rainy compared to the rest of the year (9th of 12). Daytime temperature runs 5°C above the annual average (19°C). September runs 1°C warmer than August (23°C) and cools 2°C in October (22°C).
September sunrise & sunset in San Francisco
Times shown for San Francisco local time (America/Los_Angeles), calculated for the 15th of September. They shift by a few minutes day to day across the month.
Photography light in San Francisco — September
Golden-hour and blue-hour windows for the 15th of September, in San Francisco's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — San Francisco in September
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on September's tier (Shoulder) and San Francisco's popularity.
Crowds & pricing — September in San Francisco
San Francisco is in a shoulder season month — fewer crowds, slightly lower prices, and a calmer atmosphere than peak weeks. Most major sights stay open with normal hours, though a handful of seasonal restaurants or boat trips may run reduced schedules. Many regulars consider these months the best time to visit because you trade a small amount of weather reliability for a much more pleasant on-the-ground experience.
Why this tier: excellent tourism weather peak hazard season (1 active)
Sun & mosquito risk — September in San Francisco
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
San Francisco in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 14°C / 57°F | 8°C / 46°F | 110 mm | 11 | — |
| February | 15°C / 59°F | 9°C / 48°F | 110 mm | 10 | — |
| March | 17°C / 63°F | 10°C / 50°F | 75 mm | 10 | — |
| April | 18°C / 64°F | 11°C / 52°F | 30 mm | 6 | — |
| May | 19°C / 66°F | 12°C / 54°F | 10 mm | 3 | — |
| June | 21°C / 70°F | 13°C / 55°F | 5 mm | 1 | — |
| July | 22°C / 72°F | 14°C / 57°F | 0 mm | 0 | — |
| August | 23°C / 73°F | 14°C / 57°F | 1 mm | 1 | — |
| September | 24°C / 75°F | 14°C / 57°F | 5 mm | 2 | — |
| October | 22°C / 72°F | 13°C / 55°F | 20 mm | 4 | — |
| November | 18°C / 64°F | 11°C / 52°F | 55 mm | 7 | — |
| December | 14°C / 57°F | 8°C / 46°F | 85 mm | 9 | — |
Other cities with similar September weather
🌍 See the full ranked list of climate twins for San Francisco in September →
Frequently asked questions
How hot is San Francisco in September?
In September, San Francisco averages a high of 24°C (75°F) and a low of 14°C (57°F) — generally warm.
Does it rain a lot in San Francisco in September?
September is generally dry in San Francisco, with about 2 rainy days on average.
Is September a good time to visit San Francisco?
September is warm and mostly dry. It suits travelers who are comfortable with warm weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for San Francisco in September?
Pack light layers for warm days and cooler evenings. See the full September packing list for San Francisco for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.