San Diego or Los Angeles in September?
On climate data, San Diego comes out ahead overall in September. See the per-criterion details below.
San DiegoPhoto: Rufustelestrat · CC BY 2.5
Los AngelesPhoto: Fabio Achilli from Milano, Italy · CC BY 2.0Key figures in September
| Criterion | San Diego | Los Angeles |
|---|---|---|
| Average daily high | 29 °C | 30 °C |
| Average daily low | 17 °C | 18 °C |
| Sea | 21 °C ★ | 20 °C |
| Rainy days | 1 rainy day (est.) | 1 rainy day (est.) |
| Sun | 8 h/day | 8 h/day |
| Humidity | 58 % | 51 % |
Winner by travel type
San Diego or Los Angeles in September: the short answer
In September, San Diego comes out ahead on the overall climate score (San Diego 83/100 vs Los Angeles 80/100). That is a snapshot of one month, though — which one truly fits depends on what you want from the trip, so the breakdown below goes criterion by criterion.
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 Diego averages a climate score of 76/100, 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 29 °C in San Diego and 30 °C in Los Angeles — warmer in Los Angeles. Average daily lows are around 17 °C versus 18 °C.
On rain, San Diego sees about 1 rainy days in September and Los Angeles about 1. Sunshine is comparable (8 vs 8 hours a day).
Sea temperature and swimming
In September the water is about 21 °C at San Diego and 20 °C at Los Angeles — warmer for swimming at San Diego. Neither San Diego nor Los Angeles reaches the ~21 °C swimming threshold in any month. Peak sea warmth is August for San Diego and August for Los Angeles.
Rain and sun across the year
Over a full year San Diego records roughly 39 rainy days and Los Angeles about 36 — the drier of the two overall is Los Angeles. At their sunniest, San Diego 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 Diego is at its best in May, June, 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: San Diego scores higher in September (San Diego 88 vs Los Angeles 85).
City breaks: San Diego scores higher in September (San Diego 82 vs Los Angeles 79).
Active & hiking: San Diego scores higher in September (San Diego 73 vs Los Angeles 71).
Family: San Diego scores higher in September (San Diego 86 vs Los Angeles 82).
Verdict: which should you pick?
In September, San Diego leads across every scored category here — the overall score and each travel type — so on the climate data it is the clearer pick this month. Over the year, San Diego carries the higher overall climate score. Your own priority (sun, sea, low rain or sightseeing comfort) still matters, and the month-by-month pages for each destination give you the full picture before you book.