2026 Climate Averages

Weather: San Francisco — September

The weather is near-perfect with ideal temperatures and minimal rain. Recommended month to visit.

🌟 Climate Overview

September is an excellent time to visit San Francisco. Warm weather with highs of 25°C—great for outdoor activities. Rainfall is rare, so you can leave the umbrella at home. Temperatures vary significantly between day and night—layering is recommended. As peak season, expect higher prices and more tourists. At 17°C, the sea is too cold for most swimmers.

7.8
GoTripzi Score Great

Based on weather comfort, crowds, prices, and activity options

Avg High

25°C

Avg Low

15°C

Rainy days

0days

Daylight

12.5h

Rainfall

3mm

Sunshine

11.2h/day

Humidity

73%

Humid
Sun Strength

8.1

Very High
Wind

15 km/h (gusts 35)

Sea Temp

17°C ❄️ Cold

Is September a good time to visit San Francisco?

The weather is near-perfect with ideal temperatures and minimal rain.

Now

--

Feels like --
Wind --
Humidity --
UV Index --
Local time

Air Quality

Travel Context

  • Crowds
    Very Busy
  • Travel Costs Peak Rates

Daylight

Sunrise

06:52

Sunset

19:21

12.5h daylight

Visiting San Francisco in September: Pros & Cons

Pros

  • Comfortable temperatures for sightseeing
  • Minimal rainfall — great for outdoor plans
  • Abundant sunshine for beach and outdoor fun
  • One of the best months to visit

Cons

  • Peak season — expect crowds and higher prices
  • Sea too cold for comfortable swimming
  • Very high UV — sunscreen and shade essential

Things to Do in September

Recommended for This Weather

🚶 Walking tours & sightseeing
🚲 Cycling & bike tours
🏖️ Beach relaxation & sunbathing
🥾 Hiking & nature trails
🍜 Food tours & culinary experiences
🎭 Cultural tours & local experiences

San Francisco Weather by Month

Month Avg High Avg Low Rain Sunshine Humidity UV Index Crowds Condition
Jan 15°C 7°C 7d (71mm) 7.2h
78% Humid
3.5 Moderate
Good
Feb 17°C 7°C 6d (59mm) 8.5h
72% Humid
5.2 High
Good
Mar 17°C 8°C 10d (76mm) 9.7h
72% Humid
6.7 High
Good
Apr 19°C 9°C 3d (17mm) 11.4h
70% Humid
9.3 Very High
Good
May 22°C 11°C 2d (11mm) 12.8h
68% Humid
10.8 Extreme
Good
Jun 23°C 13°C 0d (0mm) 13.4h
69% Humid
11.4 Extreme
Good
Jul 23°C 14°C 0d (0mm) 13.1h
73% Humid
11 Extreme
Good
Aug 25°C 15°C 0d (1mm) 12.4h
73% Humid
9.9 Very High
Good
Sep Current 25°C 15°C 0d (3mm) 11.2h
73% Humid
8.1 Very High
Excellent
Oct 24°C 12°C 2d (23mm) 9.5h
69% Humid
6 High
Excellent
Nov 18°C 9°C 6d (44mm) 8.1h
73% Humid
4.1 Moderate
Good
Dec 14°C 7°C 11d (109mm) 6.5h
82% Very Humid
3 Moderate
Good

⚖️Find Your Ideal Month

Adjust the sliders to weight what matters most to you.

5
3
3
Your Best MonthJunScore: 8.4

Where to Stay

See hotels, apartments & rentals around San Francisco – live prices from Booking.com, Expedia, Vrbo and more

San Francisco

San Francisco: walk the Golden Gate Bridge, tour Alcatraz, ride cable cars up steep streets, and explore a major tech innovation hub.

View Full Destination Guide

What to Pack for September

Summer clothing like shorts, t-shirts, and sundresses will be comfortable. Bring a light cardigan for air-conditioned spaces. Don't forget a wide-brimmed hat and high-SPF sunscreen — the sun is strong.

Moderate Very Busy

🎒Personalized Packing List

Tell us about your trip and we'll create a custom packing list based on the weather.

Your Packing List

📋Essentials
👕Clothing
👟Footwear
🎒Accessories
🧴Toiletries & Health

Planning a trip to San Francisco?

🔥 Peak season — book early for best rates

Frequently Asked Questions

Is September a good time to visit San Francisco?
September is typically excellent for visiting San Francisco, with average highs of 25°C and around 0 rainy days. Plan your activities accordingly—outdoor sightseeing is best on dry days, while rainy days are perfect for museums and indoor attractions.
Does it get cold at night in San Francisco in September?
Evenings in San Francisco during September are mild at 15°C. A light cardigan or long sleeves for evenings is usually enough. Outdoor dining remains comfortable, making it a great time to enjoy rooftop bars and terrace restaurants.
What should I pack for San Francisco in September?
With highs of 25°C and lows of 15°C in September, we recommend: Lightweight breathable clothes, Sunscreen SPF 30+, Sun hat, Sunglasses. Layering is key as temperatures can vary between air-conditioned interiors and outdoors. Comfortable walking shoes are essential for cobblestone streets.
Does it rain a lot in San Francisco in September?
San Francisco typically sees around 0 rainy days in September. Rain is usually in the form of brief showers rather than all-day downpours, so a compact umbrella is sufficient. Mornings tend to be drier, making them ideal for outdoor sightseeing.
Can you swim in San Francisco in September?
September is suitable for swimming in San Francisco, though the water may feel refreshing at first. Air temperatures average 25°C, and most swimmers find it enjoyable once they're in. Midday is usually the warmest time for a dip.
How many hours of daylight are there in San Francisco in September?
In September, San Francisco gets approximately 12.5 hours of daylight per day. This affects how much sightseeing you can fit in—longer days mean more time for outdoor activities, while shorter days are perfect for cozy museum visits and early dinners.
Is September peak season in San Francisco?
Yes, September is peak season in San Francisco. Expect higher prices for accommodation and more crowds at popular attractions, but also the best weather conditions. Book hotels and major attractions in advance to secure availability and better rates.

Weather Data: Based on 2020–2025 historical climate data from Open-Meteo

Solar calculations: SunCalc (timezone: America/Los_Angeles)

Last Updated: February 2026