Time difference between Hong Kong and London

The gap is not the same all year

Every converter gives one number for this pair. That number is right for most of the year and wrong for part of it, because Hong Kong does not change its clocks and London goes forward on the last Sunday in March and back on the last Sunday in October.

Hong Kong stays put all year while London moves, so the gap changes twice a year from London's side alone. A recurring meeting set in Hong Kong's calendar will drift by an hour without anyone touching it.

About Hong Kong and London

Hong Kong is UTC+8 all year and has been since 1979, when it dropped a summer-time arrangement that had run intermittently since the 1940s. It shares the offset with mainland China, which simplifies a great deal.

London is the reference the rest of the system is measured from: Greenwich sits inside the city, and UTC±0 is its winter time. It does not stay there — Britain moves to UTC+1 for seven months of the year, which is why "London is GMT" is wrong more often than it is right.

What 7 hours actually costs you

The window is 1 hour wide and that is all there is. 4:00 PM–5:00 PM in Hong Kong is 9:00 AM–10:00 AM in London, and anything outside it puts somebody at their desk when they are not meant to be. A pair this tight is worth putting in a calendar rather than agreeing each time.

When they can both be at their desks

Nine-to-five in both cities overlaps for 1 hour — 4:00 PM to 5:00 PM in Hong Kong, the same moment as 9:00 AM to 10:00 AM in London.

Hong Kong

London

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How far apart Hong Kong and London are

The shortest path over the Earth's surface between the two is 9,623 km (5,979 miles). Flown along that line, an airliner at cruising speed takes roughly 12 hours 5 minutes in the air — actual routings add to it, and whether a nonstop service exists depends on the airlines rather than the distance.

Over that distance you cross 7 hours of clock, which is where jet lag comes from: the body shifts by about an hour a day, so 7 hours takes most people 7 days or so to absorb. Flying west to London is the easier direction — you gain the hours, and staying up later comes more naturally than going to bed early.

Hong Kong to London, hour by hour

On the usual gap of 7 hours.

Frequently asked questions