DST will end at 02:00:00 AM, Sunday, Oct 27, 1918. When local clocks are to be set backward by 1 hour.

Atomic clocks are the basis upon which a second is defined. But there is a new kid on the block, the optical clock, which ...

DST will end at 02:00:00 AM, Sunday, Oct 27, 1918. When local clocks are to be set backward by 1 hour.