The United States and other some countries change their clocks two or more times a year to adjust for seasonal shifts in daylight hours. Use the following table to identify the Z command for timezones that observe daylight savings time rules.Z Commands for Daylight Savings Timezones
| Zone | Standard | Daylight | Example |
| Z28 | PST | PDT | L.A |
| Z29 | MST | MDT | Denver |
| Z30 | CST | CDT | Chicago |
| Z31 | EST | EDT | New York |
| Z32 | AST | ADT | |
| Z33 | GMT | BST | London |
| Z34 | Z34 | Z34S | Europe |
| Z35 | Z35 | Z35S | Western Australia |
| Z36 | Z36 | Z36S | Central Australia |
| Z37 | Z37 | Z37S | Australia, Sydney |
| Z38 | Z38 | Z38S | Paris |
| Z39 | Z39 | Z39S | Amsterdam |
| Z40 | USER | SMMR | customer defined |