San Francisco is 2-3 hours ahead of Honolulu. Honolulu uses Hawaii-Aleutian Standard Time (HST, UTC-10) while San Francisco uses Pacific Time (PST/PDT). When it's 12:00 PM in Honolulu, it's 2:00 PM (PST) or 3:00 PM (PDT) in San Francisco.
Hawaii does not observe daylight saving time, but California does. The difference is 3 hours during PDT (March-November) and 2 hours during PST.
Best calling time: 6:00 AM - 2:00 PM Honolulu time. This corresponds to 9:00 AM - 5:00 PM in San Francisco, covering California business hours.
Honolulu and San Francisco are connected by direct flights taking about 5.5 hours. San Francisco has a large Hawaiian community and is a major gateway for travel between Hawaii and the US mainland.