US Time Zones and How They Relate to Addresses

Geography  |  April 3, 2026  |  2 min read

The United States spans six main time zones. Knowing an address's time zone helps with delivery windows, appointment scheduling and support hours.

The main zones

• Eastern
• Central
• Mountain
• Pacific
• Alaska
• Hawaii-Aleutian

States split between zones

More than a dozen states cross a time zone line, including Texas, Florida, Tennessee, Kentucky, Indiana, Michigan, Kansas, Nebraska, North Dakota, South Dakota, Idaho and Oregon. In these states, the city or county, not the state, decides the local time.

Daylight saving time

Most of the country moves clocks forward in spring and back in fall. Arizona (outside the Navajo Nation) and Hawaii stay on standard time all year.

Using ZIP codes for time zones

ZIP code datasets often include a time zone field, which is more accurate than using the state alone. Each state and city page on this site shows the time zone for its ZIP codes.

For developers

Store time zones as IANA names like America/Chicago rather than abbreviations like CST, which are ambiguous. Test scheduling features with addresses from split states to be sure the right zone is used.