About London Time (GMT / BST)
London sits at the heart of global timekeeping. The Prime Meridian passes through the Royal Observatory in Greenwich, making London the reference point for Coordinated Universal Time (UTC). Greenwich Mean Time (GMT) has been the world's time standard since 1884, and London remains one of the most important cities for international scheduling.
During winter months (late October to late March), London observes GMT at UTC+0. In summer, clocks move forward one hour to British Summer Time (BST, UTC+1). The change occurs on the last Sunday of March at 1:00 AM GMT and reverts on the last Sunday of October.
As Europe's largest financial centre, London's business hours shape global markets. The London Stock Exchange opens at 8:00 AM and closes at 4:30 PM GMT. There is a crucial overlap window with New York markets from 1:00 PM to 4:30 PM GMT, one of the busiest trading periods in the world.
London's time zone position gives it a unique advantage for global business. Morning hours overlap with Asian markets closing, while afternoon hours coincide with the Americas opening. This makes London an ideal hub for companies operating across multiple continents.
When planning calls to London, standard business hours are 9:00 AM to 5:30 PM. Keep in mind that the UK and US switch to daylight saving time on different dates, creating brief periods where the usual 5-hour difference changes.