I second layers. Just came back from Santa Barbara via LA. Boots or closed-toe shoes, fleece or really light-weight down jacket, sweaters, jeans, long and short sleeved Ts, shirts, or sleeveless tops to wear under other layers so yo can peel off/put on throughout the day. It was 60 during the day an mid 40s at night. If it’s still raining, bring an umbrella and don’t complain about the rain. They need it–just not all at once!