Seattle is typically 8 hours behind London. When it's 5:00 PM in London, it's 9:00 AM in Seattle. 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 Seattle time (2:00 PM - 5:00 PM London). This catches afternoon business hours in London while being early morning in Seattle.
Tech companies like Amazon and Microsoft often schedule UK calls at 8:00 AM Pacific to catch London before end of day.