Updating windows daylight savings
However, this changed as rail transport and communication networks required a standardization of time unknown in Franklin's day.
In 1810, the Spanish National Assembly Cortes of Cádiz issued a regulation that moved certain meeting times forward by one hour from May 1 to September 30 in recognition of seasonal changes, but it did not actually change the clocks.
Members of the European Union conduct a coordinated shift, shifting all zones at the same instant, at Coordinated Universal Time (UTC), which means that it changes at Central European Time (CET), equivalent to Eastern European Time (EET); as a result, the time differences across European time zones remain constant.
North America shifts at but at the local time and is consequently uncoordinated - so that, for example, Mountain Time is, for one hour in the autumn, zero hours ahead of Pacific Time instead of one hour ahead and, for one hour in the spring, two hours ahead of Pacific Time instead of one hour ahead.
The manipulation of time at higher latitudes (for example Iceland, Nunavut, Scandinavia or Alaska) has little impact on daily life, because the length of day and night changes more extremely throughout the seasons (in comparison to other latitudes), and thus sunrise and sunset times are significantly out of phase with standard working hours regardless of manipulations of the clock.
The effect also varies according to how far east or west the location is within its time zone, with locations farther east inside the time zone benefiting more from DST than locations farther west in the same time zone.
In contrast, an agrarian society's daily routines for work and personal conduct are more likely governed by the length of daylight hours and by solar time, which change seasonally because of the Earth's axial tilt.
For a midnight shift in spring, a digital display of local time would appear to jump from .9 to .0.
In most countries that use daylight saving time, the time applied in the winter is considered as "standard" time and the shift is considered to be a positive offset.
The first states to adopt DST (German: Sommerzeit) nationally were those of the German Empire and its World War I ally Austria-Hungary commencing April 30, 1916, as a way to conserve coal during wartime.
Britain, most of its allies, and many European neutrals soon followed.