### B.4 Time zone items ¶

A time zone item specifies an international time zone, indicated by a small set of letters, e.g., ‘`UTC`’ or ‘`Z`’ for Coordinated Universal Time. Any included periods are ignored. By following a non-daylight-saving time zone by the string ‘`DST`’ in a separate word (that is, separated by some white space), the corresponding daylight saving time zone may be specified. Alternatively, a non-daylight-saving time zone can be followed by a time zone correction, to add the two values. This is normally done only for ‘`UTC`’; for example, ‘`UTC+05:30`’ is equivalent to ‘`+05:30`’.

Time zone items other than ‘`UTC`’ and ‘`Z`’ are obsolescent and are not recommended, because they are ambiguous; for example, ‘`EST`’ has a different meaning in Australia than in the United States. Instead, it’s better to use unambiguous numeric time zone corrections like ‘`-0500`’, as described in the previous section.

If neither a time zone item nor a time zone correction is supplied, time stamps are interpreted using the rules of the default time zone (see Specifying time zone rules).