9am in Hong Kong is 6pm in San Francisco

Hong Kong is 15 hours ahead of San Francisco. Hong Kong runs on Asia/Hong_Kong (UTC+8); San Francisco runs on America/Los_Angeles (UTC-7). The difference is measured right now; it can shift by one hour during daylight-saving-time transitions.

San Francisco observes daylight saving time — shifting between PST (UTC-8) and PDT (UTC-7) — while Hong Kong stays on HKT (UTC+8) year-round. The difference is 16 hours in San Francisco’s winter and 15 hours in San Francisco’s summer. Transitions happen in late March and late October for most Northern-Hemisphere DST zones, and late September/early April for Southern-Hemisphere ones — check the current date against the city’s DST schedule before anchoring a meeting at the edge of those windows.

Standard 9-to-5 business hours in Hong Kong and San Francisco do not overlap. Teams operating across this pair either stretch their schedules — an early-morning call from the westward city lands as an evening call in the eastward one — or rely fully on asynchronous tools. Scheduled windows at the edges (first thing for one side, last thing for the other) are the usual compromise, with one side absorbing the unsocial-hours cost this week and the other side next week.

When planning recurring meetings across Hong Kong and San Francisco, pin them to one city’s local time rather than UTC or the other city’s clock. That way, the meeting time stays stable for the person anchoring the schedule, and the other side absorbs the one-hour drift during DST transitions. The alternative — a meeting pinned to the non-DST city — means the DST city sees the meeting time “move” twice a year, which is how recurring calendar invites end up at 7am on someone’s calendar in October.