This document serves to introduce the basic terms regarding time in general and time in connection with AE.
Time is made up of a given date and a given time. The indicated time refers to the local time. It is thereby dependent on the pertinent time zone and the use (or non-use) of Daylight Savings Time.
| Los Angeles (PST) | New York (EST) | UTC | Frankfurt (CEST) | Tokyo (TYST) | 
|---|---|---|---|---|
| 
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                         | 
                         | 
                         | 
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| Friday 3rd May, 2002 | Friday 3rd  May, 2002 | Friday 3rd  May, 2002 | Friday 3rd  May, 2002 | Friday 3rd  May, 2002 | 
Date
            
The term "date" always refers to the local date. This date 
 is therefore dependent on the respective time zone and use (or non-use) 
 of Daylight Savings Time.
Time
            
The term "time" always refers to the local time. The time 
 is therefore dependent on the respective time zone and use (or non-use) 
 of Daylight Savings Time.
UTC - Coordinated Universal Time 
            
UTC is the international time standard and basis for all time calculations 
 in AE. UTC is based on the division of the day into 24 hours. Therefore, 
 afternoon times are specified, for example, as 16:00 UTC (sixteen hours, 
 zero minutes). There is no daylight savings in UTC. This way the time 
 and date specification is always precise.
GMT - Greenwich Mean Time
            
Time 
 zones are based upon Greenwich Time as the meridian (0º longitude) passes 
 through Greenwich. Greenwich Mean Time serves as the basis for calculating 
 time differences to other time zones.
TZ - TimeZone
            
The areas with time differences to UTC are called time zones. This difference 
 must not necessarily denote one full hour (60 minutes). The time zones 
 generally run along the longitudes. Within the political borders of individual 
 countries, however, the time zones can deviate from the general longitudinal 
 definition.
             
        
Date Line
            
The date line lies along the 180° line of longitude.   
Standard Time
            
Standard time is the local time assigned to the pertinent time zone. Standard 
 time is also occasionally identified as winter time.
DST 
 - Daylight Savings Time
            
For daylight savings, the standard time is adjusted forward by a certain 
 amount of time. Each individual country has its own rules on whether or 
 not Daylight Savings Time is used, the point in time for the changeover 
 and the time difference to standard time. Likewise, the chronological 
 year itself determines if and when daylight savings is implemented. Some 
 countries are currently in the process of making changes or preparing 
 to decide upon a Daylight Savings Time arrangement.
The time change from Daylight Savings Time to standard time and vice versa is most commonly 1 hour (60 minutes). Some countries, however, use a difference of more or less than one hour. Furthermore, time change in the northern hemisphere is directly opposite to that in the southern hemisphere. When in the northern hemisphere the changeover to Daylight Saving Time is made, the southern hemisphere simultaneously switches back to standard time. The switch to Daylight Saving Time in the northern hemisphere is made in the springtime, in the southern hemisphere in the fall (autumn).
See also: