Daylight Saving Time (abbreviated DST, or in England, summer time) is the convention of changing clocks so that afternoons and evenings have more daylight during warmer times of the year.
In countries north of the equator, clocks are adjusted forward one hour near the start of spring and are adjusted backward in autumn. The opposite occurs in countries in the Earth's Southern hemisphere. Often, countries near or around the equator do not honor daylight saving.
Each country may or may not honor Daylight Saving and typically it is mandated by both local and federal governments, although in some cases, they do not agree.
Often incorrectly referred to as Daylight Savings.
For more detail
- Daylight Saving on Wikipedia