Measurable snowfall in downtown Los Angeles is extremely rare. The last official accumulation was January 17, 1949—0.4 inches (1 cm) at the Civic Center.
Trace snow flurries (non-accumulating) have been reported a handful of times since, most recently in January 2019 (Malibu, West LA) and February 2019 (parts of the San Fernando Valley). These are "snow dustings"—visible but not measurable.
Drive 60–90 minutes to the San Gabriel Mountains (Mt. Baldy, Mountain High, Snow Valley) for reliable winter snow—often visible from the city on clear days.
So: Snow in LA proper is a once-in-generations event. Snow near LA is a weekly winter occurrence.