Benchmarked strictly across TripTiming's 5 empirical pillars: Crowds, Weather, Vibes, Prices, and Safety.
San Francisco emerges as the optimal December destination with an overall TripTiming Index of 68/100 vs 60/100 for Los Angeles (+8 point advantage). San Francisco experiences substantially lower visitor footfall and shorter landmark queues (moderate footfall vs peak seasonal crowding in Los Angeles). This is reinforced by lower lodging rates (~$208/night vs ~$281/night, saving ~$511 over 7 nights). While Los Angeles retains an edge in Weather Comfort (91/100 vs 82/100), San Francisco's commanding performance in Space & Crowds secures the overall December recommendation.