Colombo is in Sri Lanka and is currently on UTC+5:30. Its time zone is Asia/Colombo.
Colombo does not observe daylight saving time. It stays on UTC+5:30 all year, so the difference to any other place that also holds a fixed offset never changes.
The weekend in Colombo falls on Saturday and Sunday. A working day of 9:00 AM to 6:00 PM is the assumption used on the board.