Daylight Saving Time starts Sunday, March 14. At 2:00 a.m. on Sunday the clock moves forward to 3:00 a.m., adding an extra hour of daylight until November. Daylight Saving Time (DST) was first observed in the US in 1918. Enacted in 1966, the federal Uniform Time Act gives states two options – year round standard time or DST. California currently follows DST.
In 2018 the California voters approved Proposition 7 by nearly 60% that allows the state Senate to adopt year round DST with a 2/3 vote (which will only become operative if authorized by federal law). The California Senate has not yet approved a switch to DST. California’s DST law can be found at Government Code 6808.
Only two states, most of Arizona (excluding the Navajo Nation) and Hawaii (and the US territories), do not observe DST. Arizona, except NN, stays on Mountain Standard Time (MST) year round. Hawaii is on Hawaii Standard Time (HST) all year, two hours behind San Diego.
For more info about state actions related to DST around the country see: Daylight Saving Time | State Legislation (ncsl.org)
Read more about the history of Daylight Saving Time here.