Managing time zones

You can manage time zones in the Time zones application, where you can see a list of defined time zones.

Creating a new time zone

In the following example, you will learn how to create a new time zone:

Open the Time zones application.
Click New time zone.
Fill in the details of the new time zone.
- See Configuring daylight saving time below.
Click Save.

You have just created the time zone. Now if you switch back to the time zones list, you should see the new time zone present among the records.

Time zone properties

When defining a new time zone or editing an existing one, you can set the following properties:

Time zone name	Display name of the time zone.
Code name	Code name of the time zone.
GMT difference	Difference in hours between the time zone and Greenwich Mean Time.
Use daylight saving time	If checked, daylight saving time (DST) will be used for this time zone. Values set in the DST start rule and DST end rule properties will be used to define the DST interval.
DST starts at	Based on values set in DST start rule, this field will display the exact time when the time advance will occur.
DST ends at	Based on values set in DST end rule, this field will display the exact time when the time advance will be rolled back.
DST start rule & DST end rule	Using these sets of properties, you can exactly define when the time advance should be carried out.
Month	Month in which the time advance occurs.
Condition	Condition specifying the day that the change occurs on. Based on the selected option, you can select day of the week, day number or a combination of both.
Day	Two fields – day of the week and day number – can be used based on the selected condition.
Time	Exact time of the time advance.
Value	Number of hours that will be added to the current time when the time advance occurs.

Configuring daylight saving time

When creating a time zone or modifying an existing one, you may need to specify the daylight saving time (DST). This is a convention of setting clocks so that afternoons have more daylight and mornings have less of it. The amount of time advance and dates of change vary from country to country, however, it is usually a one hour advance at the beginning of spring and the advance is rolled back in autumn.

For more information about DST, see this article: http://en.wikipedia.org/wiki/Daylight_saving_time.

You can set the daylight saving time separately for each of the time zones when creating a new time zone or when editing an existing one:

Select the Use daylight saving time check box.

Set the DST start rule for the current time zone.

First, select the month in which the change will be carried out using the Month drop-down list.

Specify on which day of the selected month the change will be carried out using the Condition drop-down list and the two Day drop-down lists.

FIRST	Day of the week can be selected. If you select Monday, the time advance will occur on the first Monday of the selected month.
LAST	Day of the week can be selected. If you select Monday, the time advance will occur on the last Monday of the selected month.
>=	Day of the week and day number can be selected. If you select Monday and 15, the time advance will occur on the first Monday after the 15th day of the selected month.
<=	Day of the week and day number can be selected. If you select Monday and 15, the time advance will occur on the last Monday before the 15th day of the selected month.
=	Day number can be selected. If you select 15, the time advance will occur on the 15th of the selected month.

Set the time when the change will occur on the specified date using the Time field.
Set the time difference between the standard time and DST in the Value field.
- This value represents the difference from standard time in hours.
- Use this value (usually 1) for the DST start rule and 0 for the DST end rule.

Set the DST end rule as specified in the previous step. Set Value as 0.
Click Save.