Home > Time Zones > Daylight Saving Time > Transition to DST

Transitioning Into Daylight Saving Time

The World Clock features a list of cities where you can view information about that city including if it observes Daylight Saving Time.

How does the transition start?

For example: DST starts at 2:00 am local time and DST will move the clocks forward one hour - the seconds before and after the "Spring forward" are listed in the following table:

DST start transition
Local timeDST or standard?Comments
3:00:00DSTDST starts, time advanced by one hour

Note that the local time between 2:00:00 — 2:59:59 does not exist during the transition from standard time to DST. This hour is skipped, therefore this day only consists of 23 hours.

Anyone who worked during the night from midnight to 8:00 a.m. has worked only seven hours because of the skipped hour.

How does the transition to DST end?

For Example: DST ends at 2:00 a.m. local time and the switch back to standard time will move the clocks back one hour:

DST end transition
Local timeDST or standard?Comments
time from 1:00:02 to 1:59:57 daylight saving time not shown
1:00:00standardTime is turned back to standard time
time from 1:00:02 to 1:59:57 standard time not shown

Note that the local time from 1:00:00 to 1:59:59 is repeated this day. It first occurs during DST time, then clocks are turned back one hour to standard time and the time is repeated during standard time.

To avoid confusion, when referring to time within this hour, it is important to mention whether it was before or after the change back to standard time. The day consists of 25 hours when DST ends.

Anyone who worked during the night from midnight to 8:00 a.m. has worked for nine hours because of the repeated hour.

Topics: Daylight Saving Time, Timekeeping

You might also like

10 Facts: Total Lunar Eclipse

10 Facts: Total Lunar Eclipse

The April 4, 2015 Total Lunar Eclipse is the third eclipse in a series of four Total Eclipses of the Moon called Eclipses of the Blood Moon. 10 facts about the eclipse. more

Daylight Saving Time – DST

Daylight Saving Time aka Daylight Savings Time, DST or Summer Time. Clocks go forward 1 hour in the spring and back in the fall to make better use of daylight. more

GMT or BST in the UK?

The UK is not on Greenwich Mean Time (GMT) all year. During Daylight Saving Time the correct time zone is British Summer Time (BST). more

The Daylight Saving Time Debate

DST has become a political issue, while others debate whether setting the clocks one hour ahead in the spring has the intended effect of conserving energy or reducing road accidents. more