United States San Francisco Weather in September (Indian summer — best month) — Climate Guide
September (Indian summer — best month) in San Francisco is Excellent
San Francisco Weather in September (Indian summer — best month) — Quick Answer
As of 2026- Avg temp
- 22° / 14°
- Rainfall
- 8mm · 1 days
- Crowds
- Very busy
As of 2026, San Francisco in September (Indian summer — best month) averages a high of 22°C and low of 14°C with 8mm of rain over about 1 days. Early autumn / Indian summer — high 22°C, low 14°C. T-shirt + cardigan. Sunglasses + sunscreen. Layers still ready for cool nights.
September (Indian summer — best month) is Excellent for San Francisco.
September is the single best month to visit San Francisco. Indian summer brings 22/14°C, 95% sunny days, fog gone, perfect light for photos. Hotels remain pricey but the weather payoff is real. Locals consider this the best month every year without exception.
Travel score
San Francisco September (Indian summer — best month) Weather Stats
Avg High
22°C
Avg Low
14°C
Rainy Days
1
8mm total
Sunshine
10h
Daily avg
Humidity
73%
Comfortable
UV Index
8
Very high
Wind
13 km/h
Gusts 28
Sea Temp
16°C
Avg water temp
Crowds
Very busy
At attractions
September (Indian summer — best month) Sunrise & Sunset
Air Quality
PM2.5
9 μg/m³
PM10
18 μg/m³
Status
Good
Feels-Like Temperature & Wind
Feels like
Daytime
22°C
Nighttime
14°C
Humidity and wind affect how the actual temperature feels.
Wind
13 km/h
Max gust 28 km/h
Activities Recommended for September (Indian summer — best month)
September (Indian summer — best month) Travel Pros & Cons
Pros
- Weather 22/14°C ideal
- 95% sunny days
- No fog
Cons
- Hotel rates peak
September (Indian summer — best month) Events & Festivals
- Indian summer — SF's warmest weather of the year
San Francisco in September (Indian summer — best month) — Full Picture
September is the single best month to visit San Francisco. Indian summer brings 22/14°C, 95% sunny days, fog gone, perfect light for photos. Hotels remain pricey but the weather payoff is real. Locals consider this the best month every year without exception.
What to Wear & What to Pack
Early autumn / Indian summer — high 22°C, low 14°C. T-shirt + cardigan. Sunglasses + sunscreen. Layers still ready for cool nights.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
17.3°C
11°C
5.3/mo
Summer (Jun·Jul·Aug)
19.3°C
13.3°C
0.3/mo
Autumn (Sep·Oct·Nov)
Current20.3°C
12.7°C
3.7/mo
Winter (Dec·Jan·Feb)
14.3°C
8.3°C
10.3/mo
San Francisco Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| 14° | 8° | 11d·110mm | 5h | 75% | 3 | Quiet | Low season | |
| 15° | 9° | 10d·110mm | 6h | 73% | 4 | Quiet | Low season | |
| 16° | 10° | 8d·75mm | 8h | 70% | 5 | Moderate | Shoulder | |
| 17° | 11° | 5d·35mm | 9h | 70% | 7 | Moderate | Shoulder | |
| May (Best) | 19° | 12° | 3d·18mm | 10h | 70% | 8 | Busy | Peak |
| 19° | 13° | 1d·5mm | 9h | 75% | 9 | Very busy | Peak | |
| 19° | 13° | 0d·0mm | 9h | 78% | 10 | Very busy | Peak | |
| 20° | 14° | 0d·0mm | 9h | 78% | 9 | Very busy | Peak | |
| 22° | 14° | 1d·8mm | 10h | 73% | 8 | Very busy | Peak | |
| 21° | 13° | 3d·28mm | 8h | 73% | 6 | Very busy | Peak | |
| 18° | 11° | 7d·70mm | 7h | 73% | 4 | Busy | Peak | |
| 14° | 8° | 10d·110mm | 5h | 75% | 3 | Very busy | Peak |
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San Francisco September (Indian summer — best month) Hotel Picks
Frequently Asked Questions
Is September (Indian summer — best month) a good time to visit San Francisco?
San Francisco in September (Indian summer — best month) is Excellent. Tourist crowds are very busy and flight/hotel prices are peak.
What's the average temperature in San Francisco in September (Indian summer — best month)?
San Francisco September (Indian summer — best month) averages a high of 22°C and a low of 14°C.
Does it rain much in San Francisco in September (Indian summer — best month)?
San Francisco September (Indian summer — best month) averages 8mm of rainfall over about 1 rainy days.
What should I wear in San Francisco in September (Indian summer — best month)?
Early autumn / Indian summer — high 22°C, low 14°C. T-shirt + cardigan. Sunglasses + sunscreen. Layers still ready for cool nights.
What time are sunrise and sunset in San Francisco in September (Indian summer — best month)?
San Francisco September (Indian summer — best month) sunrise is 06:50 and sunset is 19:25, with 12h 35m of daylight.
What's the air quality like in San Francisco in September (Indian summer — best month)?
San Francisco September (Indian summer — best month) air quality (AQI) averages 35, rated Good. PM2.5 averages 9μg/m³.
What activities are recommended in San Francisco in September (Indian summer — best month)?
In September (Indian summer — best month), San Francisco is great for Golden Gate Bridge bike, Alcatraz, Ferry Building Saturday market.
Is September (Indian summer — best month) peak season in San Francisco?
San Francisco September (Indian summer — best month) crowds are very busy and prices are peak. Advance reservations are strongly recommended.
Best Months to Visit San Francisco
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Planning a September (Indian summer — best month) trip to San Francisco?
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Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.