#Standard time zones how to#
#Standard time zones code#
#Standard time zones free#

For example, if this transition occurs on a particular day at 2:00 A.M. An invalid time is a nonexistent time created by the transition from standard time to daylight saving time. For example, a transition from standard time to daylight saving time that occurs on the third Sunday of March follows a floating adjustment rule.įor time zones that support adjustment rules, the transition to and from daylight saving time creates two kinds of anomalous times: invalid times and ambiguous times. Much more common are floating adjustment rules, which set a particular day of a particular week of a particular month for the transition to or from daylight saving time. For example, a transition from daylight saving time to standard time that occurs each year on October 25 follows a fixed adjustment rule. A fixed adjustment rule sets a particular date on which the transition to or from daylight saving time occurs each year. The transition to and from daylight saving time in a particular time zone can be defined either by a fixed or a floating adjustment rule. These changes to and from standard time are known as adjustment rules. Daylight saving time tries to maximize daylight hours by advancing the time forward by one hour in the spring or early summer, and returning to the normal (or standard) time in the late summer or fall. Many of the world's time zones support daylight saving time. The time in any of the world's time zones can be expressed as an offset from Coordinated Universal Time (UTC). Typically, but not always, adjacent time zones are one hour apart. Time zone essentialsĪ time zone is a geographical region in which the same time is used. You can also use TimeZoneInfo to define custom time zones that the system has no information about. The TimeZoneInfo class supports both of these zones as well as any time zone about which information is predefined in the registry.

The TimeZone class supports working with the local time zone and Coordinated Universal Time (UTC). It takes a single parameter, which is the date and time value to convert.The TimeZoneInfo class simplifies the creation of time zone-aware applications. The TimeZone.ToLocalTime method behaves identically to the DateTime.ToLocalTime method. DateTime.KindĪssumes that the DateTime value is UTC and converts the UTC to local time.Ĭonverts the DateTime value to local time. The exact behavior of the method depends on the value of the object's Kind property, as the following table shows. To convert UTC to local time, call the ToLocalTime method of the DateTime object whose time you want to convert.

IIf(cstZone.IsDaylightSavingTime(cstTime), _ĬstZone.DaylightName, cstZone.StandardName))Ĭonsole.WriteLine('The registry does not define the Central Standard Time zone.')Ĭonsole.WriteLine('Registry data on the Central Standard Time zone has been corrupted.') DateTime dateNow = DateTime.Now Ĭonsole.WriteLine('The date and time are.

#Standard time zones code#

The following code converts the current local time to UTC and displays the result to the console. Returns the dateTime parameter unchanged. DateTime.KindĪssumes the dateTime parameter is local time and converts local time to UTC. The exact conversion performed by the method depends on the value of the dateTime parameter's Kind property, as the following table shows. The easiest way to convert a time to UTC is to call the static ( Shared in Visual Basic) TimeZoneInfo.ConvertTimeToUtc(DateTime) method. Because DateTimeOffset objects store a date and time value along with its offset from UTC, they always represent a particular point in time in relationship to UTC. You can also serialize a DateTimeOffset structure to unambiguously represent a single point in time. NET Framework.) Converting individual time zones to UTC makes time comparisons easy. (For details and other best practices using dates and times, see Coding best practices using DateTime in the.

The use of UTC time is recommended when a date and time's portability across computers is important.

#Standard time zones free#

Thus, UTC provides a kind of time-zone free or time-zone neutral time. The world's time zones are expressed as positive or negative offsets from UTC. Converting to Coordinated Universal TimeĬoordinated Universal Time (UTC) is a high-precision, atomic time standard.

#Standard time zones how to#

This topic explains how to convert times from one time zone to another, as well as how to convert DateTimeOffset values that have limited time zone awareness. For example, a Web page that displays the current time in the eastern part of the United States will lack credibility to a customer in eastern Asia. An application can no longer assume that all times can be expressed in the local time, which is the time available from the DateTime structure. It is becoming increasingly important for any application that works with dates and times to handle differences between time zones.