1.14 Time zones
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## 1.14 Time zones

The whole globe is divided into 24 parts which are called time zones. The individual time zones are defined by their shift from UTC (Coordinated Universal Time). In most cases, the time is shifted by one hour, but sometimes this shift can be 30 or 15 minutes.

From the geographical point of view, the time zones are delimited by meridians. One time zone (and one meridian) was defined as the origin; it is the meridian of Greenwich. This meridian is also called the “zero” or Greenwich Meridian. The zone of this meridian uses the universal time (UTC), which is the same as GMT (Greenwich Mean Time). Both abbreviations, UTC and GMT, are used for defining time zones and have approximately the same meaning. Kerio WebMail uses the GMT time.

The method of time zone indication depends on location of the selected time zone (to the east or west from the Greenwich meridian). If the zone is located east of the greenwich meridian, the time displacement is indicated by the `+` sign. The zones located west of the meridian are indicated by `-`.

The time zone issue gets event more complicated, when it is necessary to consider the winter time and the daylight saving time. Thus, the real shift of the local time from the GMT may vary in the course of the year. Kerio WebMail considers the winter time and the daylight saving time for the selected time zone automatically.

Kerio WebMail shows the time zones in the following manner:

`GMT +12` (Fiji)

`GMT -6` (Easter Island)

The counterpart of the zero meridian is so-called date line which makes a division between the `GMT -12` a `GMT +12` time zones. The date line is not a meridian, because it does not form any connection between the North and South Pole. It just separates two time zones so that one state does not belong to two different time zones at a moment. When you cross the line from the east to the west, a day is added. When you cross from west to the east, a day is subtracted.

### 1.14.1 Change of a time zone

The time zone is set by the Kerio MailServer machine time by default. It can be changed in Kerio WebMail in the user settings on the General tab (see chapter 1.12.1 User settings).

### Warning

When the time zone is changed, the time of entering the events and meetings into the calendar is affected.

### 1.14.2 Events in different time zones

For the delivered messages as well as event settings, Kerio WebMail shows the time of the time zone currently selected. The following text illustrates setting of events for different time zones and the time shown:

The events in Kerio MailServer are stored together with the information about the time zone in which they were created as well as the daylight savings time (if specified). To display the event in a different time zone, Kerio WebMail converts it automatically (including the daylight savings time, if specified for the given time zone).

If you log in to Kerio WebMail from a different time zone or if another user displays your Free/Busy calendar, the time will be converted automatically (including the daylight savings time, if specified in.Kerio WebMail).

The following examples illustrate the principle of time zones:

Example 1:

You live in London. Your time zone is GMT +0. A friend from New York invites you for a lunch and you arrange a meeting with him for 14:00 hours. Keep in mind that your friend means 14:00 in his time zone, i.e. in GMT -5 (Eastern Time). You have to switch to the friend's time zone in Kerio WebMail and create an event with beginning at 14:00.

Example 2:

Imagine the previous (Example 2) event, but from the other point of view. If your friend sends an invitation for 14:00, it will be displayed as a meeting at 20:00 in your time zone (including daylight saving time). However if you switch the time zone to Eastern Time after you arrive to New York, the meeting will show the correct time — 14:00.

#### Behavior of the Free/Busy calendar

The events in Kerio MailServer are stored together with the information about the time zone in which they were created as well as the daylight savings time (if specified). Thus, it does not matter in which time zone the event was created. The present status will be displayed in the Free/Busy (the free/busy information for individual attendees is converted to the time zone specified in your Kerio WebMail).

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