Central Daylight Time (CDT) is a time zone that is 5 hours behind Coordinated Universal Time (UTC-5). It is observed during the warmer months when clocks are set forward by one hour to make better use of daylight. CDT typically runs from the second Sunday in March to the first Sunday in November. This time zone is used in several regions, including parts of the United States and Canada. Major cities like Chicago, Dallas, and New Orleans observe CDT. When Daylight Saving Time ends, these areas revert to Central Standard Time (CST), which is UTC-6.