San Francisco or Los Angeles in September?
In September, San Francisco and Los Angeles are overall neck and neck — it comes down to your priorities.
San FranciscoPhoto: Dale Cruse · CC BY 2.0
Los AngelesPhoto: Fabio Achilli from Milano, Italy · CC BY 2.0Key figures in September
| Criterion | San Francisco | Los Angeles |
|---|---|---|
| Average daily high | 24 °C | 30 °C |
| Average daily low | 13 °C | 18 °C |
| Sea | 15 °C | 20 °C ★ |
| Rainy days | 1 rainy day (est.) | 1 rainy day (est.) |
| Sun | 7 h/day | 8 h/day ★ |
| Humidity | 70 % | 51 % |
Winner by travel type
Trade-offs
- Los Angeles is about 6 °C warmer by day.
- The sea at Los Angeles is about 6 °C warmer.
San Francisco or Los Angeles in September: the short answer
In September, San Francisco and Los Angeles are essentially level on the overall climate score (both around 80/100). The decision comes down to the individual criteria below.
This comparison focuses on September as a representative month for the pair; for any other month, use each destination's month-by-month pages. Across the whole year San Francisco averages a climate score of 61/100, Los Angeles 75/100. Both profiles below are historical monthly averages, not a forecast.
Weather in September, side by side
The average daily high is about 24 °C in San Francisco and 30 °C in Los Angeles — warmer in Los Angeles. Average daily lows are around 13 °C versus 18 °C.
On rain, San Francisco sees about 1 rainy days in September and Los Angeles about 1. Los Angeles gets more sunshine (7 vs 8 hours a day).
Sea temperature and swimming
In September the water is about 15 °C at San Francisco and 20 °C at Los Angeles — warmer for swimming at Los Angeles. Neither San Francisco nor Los Angeles reaches the ~21 °C swimming threshold in any month. Peak sea warmth is September for San Francisco and August for Los Angeles.
Rain and sun across the year
Over a full year San Francisco records roughly 66 rainy days and Los Angeles about 36 — the drier of the two overall is Los Angeles. At their sunniest, San Francisco reaches about 10 hours of sun a day (June) and Los Angeles about 10 (June). If dependable dry, sunny weather is your top priority, weigh these annual totals alongside the single month above.
Best time to visit each
Climatically, San Francisco is at its best in July, August, September and October, while Los Angeles peaks in May, June, September and October. If your dates are fixed, pick the destination whose strong season overlaps them; if you are flexible, plan around these windows.
Which suits which kind of trip
Based on the September scores for each travel style:
Beach & swimming: Los Angeles scores higher in September (San Francisco 69 vs Los Angeles 85).
City breaks: San Francisco scores higher in September (San Francisco 98 vs Los Angeles 79).
Active & hiking: San Francisco scores higher in September (San Francisco 89 vs Los Angeles 71).
Family: Los Angeles scores higher in September (San Francisco 74 vs Los Angeles 82).
Verdict: which should you pick?
There is no single winner — it depends on your month and your priority. For September specifically, use the head-to-head above; over the year, Los Angeles carries the slightly higher overall climate score. Choose San Francisco if its strong months and profile match your plan, Los Angeles if its do. The month-by-month pages for each destination give you the full picture before you book.