Thanks to prevailing weather patterns and the extreme geography around Los Angeles we often get entire months where the Pacific Marine Layer comes onshore every night and blots out the sun for almost all the day. Los Angeles is located in a series of bowls, with steep mountains on three sides. This traps the marine layer over the populated parts of the city. To see some blue sky in those months it's necessary to get up/over the mountains.

This photo was taken at Echo Mountain, at the end of the Sam Merrill Trail in Altadena. The "island" in the middle of the marine layer is the Verdugo Mountains, and the San Gabriel Mountains are on the right of the frame.

The marine influence is a moderating factor in Los Angeles weather. When it's 45C in inland California, it will often be a moderate 25C in Los Angeles. When the marine layer breaks down then temperatures will soar in LA. As of 2024, my Los Angeles neighborhood holds the heat record for Los Angeles County of 49.4C (121F).