Chilly during the day too! If you're a desert-dweller acclimated to 110° summers, 55° on a November afternoon is honestly kinda cold.
Having lived in both SoCal and Vegas, the difference is that Vegas is both hotter in the winter and colder in the summer... whereas a place like San Diego is blissfully mild year-round.
55F is just starting to get cool, could be a beautiful day if the sun is shining. "cold" don't start till the 40s and if you're working theres still great days in the 30s.
Having lived in both SoCal and Vegas, the difference is that Vegas is both hotter in the winter and colder in the summer... whereas a place like San Diego is blissfully mild year-round.