Manual Time zone Selection
Usually, it is not necessary and not recommended to select the time zone manually, because this computer program knows which time zones apply to which places for what times, and has complete information about daylight saving time.
In some very rare cases a user may have better information about time zones and daylight saving time than the database used here. For example, there are areas of doubt for some years in Vietnam, and for many parts of the former Soviet Union.
In such cases it may be necessary to turn the automatic time zone selection off by clicking the checkbox. In the next step after clicking on "continue", a pulldown list will appear where the applicable time zone can be selected. If the first entry is chosen, you will return to automatic mode.