San Francisco is typically 8 hours behind London. When it's 5:00 PM in London, it's 9:00 AM in San Francisco. Both cities observe daylight saving time, though the transition dates differ slightly.
During the brief periods when the US and UK change clocks on different weekends (usually in March and November), the difference can temporarily be 7 or 9 hours. For most of the year, it's a consistent 8-hour difference.
Optimal meeting window: 6:00 AM - 9:00 AM San Francisco time (2:00 PM - 5:00 PM London). This catches afternoon business hours in London while being early morning in SF.
Tech companies often schedule standups at 8:00 AM Pacific to catch London colleagues before end of day.