double summer time
noun1
Historical The advancing of clocks by two hours ahead of winter time in the summer instead of the usual one hour; mainly used during World War II in the United Kingdom.
- Double summertime in Ireland had some curious effects on timetables, seeing that in Eire the single additional hour only was worked to, whereas in Northern Ireland the full British two-hour addition was in operation.1941 September, “Notes and News: Timetable Puzzles in Ireland”, in Railway Magazine, page 428: