| UTC | EDT/AST | CDT/EST | MDT/CST | PDT/MST | PST |
|---|---|---|---|---|---|
| 0000* | 2000 | 1900 | 1800 | 1700 | 1600 |
| 0100 | 2100 | 2000 | 1900 | 1800 | 1700 |
| 0200 | 2200 | 2100 | 2000 | 1900 | 1800 |
| 0300 | 2300 | 2200 | 2100 | 2000 | 1900 |
| 0400 | 0000* | 2300 | 2200 | 2100 | 2000 |
| 0500 | 0100 | 0000* | 2300 | 2200 | 2100 |
| 0600 | 0200 | 0100 | 0000* | 2300 | 2200 |
| 0700 | 0300 | 0200 | 0100 | 0000* | 2300 |
| 0800 | 0400 | 0300 | 0200 | 0100 | 0000* |
| 0900 | 0500 | 0400 | 0300 | 0200 | 0100 |
| 1000 | 0600 | 0500 | 0400 | 0300 | 0200 |
| 1100 | 0700 | 0600 | 0500 | 0400 | 0300 |
| 1200 | 0800 | 0700 | 0600 | 0500 | 0400 |
| 1300 | 0900 | 0800 | 0700 | 0600 | 0500 |
| 1400 | 1000 | 0900 | 0800 | 0700 | 0600 |
| 1500 | 1100 | 1000 | 0900 | 0800 | 0700 |
| 1600 | 1200 | 1100 | 1000 | 0900 | 0800 |
| 1700 | 1300 | 1200 | 1100 | 1000 | 0900 |
| 1800 | 1400 | 1300 | 1200 | 1100 | 1000 |
| 1900 | 1500 | 1400 | 1300 | 1200 | 1100 |
| 2000 | 1600 | 1500 | 1400 | 1300 | 1200 |
| 2100 | 1700 | 1600 | 1500 | 1400 | 1300 |
| 2200 | 1800 | 1700 | 1600 | 1500 | 1400 |
| 2300 | 1900 | 1800 | 1700 | 1600 | 1500 |
| 2400* | 2000 | 1900 | 1800 | 1700 | 1600 |
Coordinated Universal Time (UTC) is the time at the zero or reference meridian. Time changes one hour with each change of 15 degrees in longitude. The five time zones in the US proper and Canada roughly follow these lines.
* 0000 and 2400 are interchangeable. (2400 is associated with the date of the day ending, 0000 with the day just starting.)