Pictured is a world map image of states, countries and territories that use daylight savings time (DST), don’t use DST or have used DST in the past. Blue represents those that use DST. Red are those that don’t use DST. Orange are those that have used DST in the past.
Most areas in North America and Europe, and some areas in the Middle East observe DST while most areas of Africa and Asia do not. In South America most countries in the north of the continent near the equator do not observe DST, while Paraguay and southern parts of Brazil do. Oceania is also mixed, with New Zealand and parts of southeastern Australia observing DST, while most other areas do not.
Daylight saving time (DST) or summer time is the practice of advancing clocks during summer months by one hour so that in the evening daylight is experienced an hour longer, while sacrificing normal sunrise times. Typically, users in regions with summer time adjust clocks forward one hour close to the start of spring and adjust them backward in the autumn to standard time.
New Zealander George Hudson proposed the modern idea of daylight saving in 1895. Germany and Austria-Hungary organized the first implementation, starting on 30 April 1916. Many countries have used it at various times since then, particularly since the energy crisis of the 1970s.
The practice has received both advocacy and criticism. Putting clocks forward benefits retailing, sports, and other activities that exploit sunlight after working hours, but can cause problems for evening entertainment and for other activities tied to sunlight, such as farming. Although some early proponents of DST aimed to reduce evening use of incandescent lighting, which was formerly a primary use of electricity, modern heating and cooling usage patterns differ greatly and research about how DST currently affects energy use is limited or contradictory.
DST clock shifts sometimes complicate timekeeping and can disrupt travel, billing, record keeping, medical devices, heavy equipment, and sleep patterns. Computer software can often adjust clocks automatically, but policy changes by various jurisdictions of the dates and timings of DST may be confusing.
Information source: Wikipedia.org.