London uses Greenwich Mean Time (GMT), equivalent to UTC, during the winter clock period. In summer it uses British Summer Time (BST), UTC+1. To see the current minute, add London to your phone’s world clock. The named city setting follows seasonal changes automatically. A clock permanently set to GMT will be an hour behind London during BST. London, Edinburgh, Cardiff, and Belfast use the same civil time, so a trip between those cities requires no clock adjustment.

London is usually five hours ahead of New York. When both places are on standard time, 9 a.m. in New York is 2 p.m. in London. The same example works when both use summer time. During the short spring and autumn periods when the U.S. is on daylight time and the UK is on GMT, the gap shrinks to four hours. A 9 a.m. New York call then starts at 1 p.m. in London. Check the event’s specific date before relying on the usual five-hour difference.

London is usually six hours ahead of Dallas and eight ahead of Los Angeles. For example, 10 a.m. in Dallas normally corresponds to 4 p.m. in London, and 8 a.m. in Los Angeles normally corresponds to the same London time. During the mismatched clock-change periods, those differences become five and seven hours. If your group includes people in all three cities, enter the meeting in a calendar using named time zones. That is easier to maintain than manually adjusting three recurring reminders.

Under the published UK schedule, clocks move forward on March 28, 2027, and back on October 31, 2027. The spring change jumps from 1 a.m. GMT to 2 a.m. BST, so that night skips an hour. The autumn change moves from 2 a.m. BST back to 1 a.m. GMT, repeating an hour. If you are arranging an overnight transfer or an automated job, include the time-zone abbreviation or UTC offset so the repeated hour cannot be confused.

When the gap is six hours, 8 p.m. Monday in Dallas becomes 2 a.m. Tuesday in London. The date changes as soon as the calculation crosses midnight. Airline itineraries typically show local departure and arrival times, so subtracting the displayed clock times alone will not give the flight duration. Convert both timestamps to the same time zone, include their dates, and then subtract. For a family call, confirm the day and date on both sides before sending an invitation.