Best overlap: 8:30 AM to 12:30 PM in Manchester is 2:00 PM to 6:00 PM in Colombo.
Shoot for 8:30 AM to 12:30 PM in Manchester; your Colombo colleagues will see that as 2:00 PM to 6:00 PM. Colombo is 5.5 hours ahead of Manchester, so the practical overlap is about 4 hours — generous enough for meetings, tight enough to be worth booking ahead. Daylight saving complicates things slightly: Manchester observes it, Colombo doesn't, so the difference flexes by an hour part of the year.
London to New York is five hours apart, except for the five weeks a year when it isn't. Exact overlap windows for every US zone, the 2026 DST mismatch dates, and where to put the recurring sync. -