The Central Time Zone is the band of North America that runs six hours behind Coordinated Universal Time in winter (Central Standard Time, UTC−6) and five hours behind in summer (Central Daylight Time, UTC−5). In the United States it covers ten states in full and parts of ten more, and it extends into Canada, Mexico, and all of Central America. Federal regulations at 49 CFR Part 71 draw the exact boundaries down to the county line, and the Secretary of Transportation has authority to move those lines.
Which States Are on Central Time
Nine states sit entirely inside the Central zone under 49 CFR § 71.6: Alabama, Arkansas, Illinois, Iowa, Louisiana, Minnesota, Mississippi, Missouri, and Wisconsin.1Legal Information Institute (LII). 49 CFR Part 71 – Standard Time Zone Boundaries Oklahoma also lies entirely within the zone, defined by the boundary descriptions in the surrounding sections rather than named in the list. Residents of these ten states never cross a time zone line without leaving the state.
Ten more states are split. On the eastern edge, parts of Florida, Indiana, Kentucky, Michigan, and Tennessee observe Central Time while the rest run on Eastern. On the western edge, parts of Kansas, Nebraska, North Dakota, South Dakota, and Texas fall into Mountain Time rather than Central.
The size of the split varies a lot. Kansas puts only four far-western counties on Mountain Time. South Dakota is cut roughly down the middle. Texas keeps almost the entire state on Central, with only El Paso County, Hudspeth County, and a sliver of Culberson County near Guadalupe Mountains National Park on Mountain Time. If you live near one of these boundaries, the practical time zone for your day-to-day life may be the one across the county line, not the one the state is usually associated with.
International Reach
Central Time is not just an American zone. In Canada, Manitoba is entirely on Central Time, and parts of Ontario, Nunavut, and Saskatchewan follow it as well.2National Research Council Canada. Time Zones and Daylight Saving Time Most of Saskatchewan stays on Central Standard Time year-round and does not observe daylight saving.
In Mexico, the central and eastern regions, including Mexico City, use Central Standard Time. Since Mexico abolished daylight saving for most of the country in late 2022, those areas stay on UTC−6 year-round. Municipalities along the U.S. border are the exception and still follow the American DST schedule to stay in sync with the U.S. side. In Central America, Belize, Costa Rica, El Salvador, Guatemala, Honduras, and Nicaragua all observe UTC−6 all year with no seasonal change, so they line up permanently with Central Standard Time.
CST vs. CDT: The Offsets and When Clocks Change
The zone runs on two offsets that alternate with the seasons. Central Standard Time (CST) is UTC−6. Central Daylight Time (CDT) is UTC−5.3U.S. Naval Observatory. U.S. Time Zones The gap between them is one hour of clock time.
The switch dates are set by federal law and are the same every year. Clocks spring forward on the second Sunday of March at 2:00 a.m. local time, jumping to 3:00 a.m. They fall back on the first Sunday of November at 2:00 a.m. local time, dropping to 1:00 a.m.4U.S. Naval Observatory. Daylight Saving Time That schedule has been in place since 2007, when Congress lengthened the daylight saving period. States cannot pick their own start or end dates; they either follow this schedule or opt out of DST entirely.
How Central Time Lines Up With Other U.S. Zones
Central sits in the middle of the continental U.S. sequence. It runs one hour behind Eastern, one hour ahead of Mountain, and two hours ahead of Pacific. Under 15 U.S.C. § 261, the country is divided into nine zones, each offset from UTC by a whole number of hours, with Central at UTC−6.5Office of the Law Revision Counsel. 15 USC 261 – Zones for Standard Time; Interstate or Foreign Commerce Adjacent zones always differ by exactly one hour, which is why 8 p.m. Eastern is 7 p.m. Central and 6 p.m. Mountain without any awkward math.
Everyday Effects to Watch For
Financial Markets
The major U.S. stock exchanges run on Eastern Time, so Central Time investors get an earlier start. The NYSE’s core session of 9:30 a.m. to 4:00 p.m. ET is 8:30 a.m. to 3:00 p.m. CT.6NYSE. Holidays and Trading Hours The bond market’s local session in Central Time runs 7:00 a.m. to 4:00 p.m. CT.
Television
National broadcast networks generally send a single eastern feed that airs at the same instant in the Eastern and Central zones. Primetime starts at 7:00 p.m. Central instead of 8:00 p.m. That is what “8/7 Central” in TV listings has always meant.
The Tax Court Deadline Trap
Most federal filing deadlines are set in the filer’s local time zone, so a Central Time resident usually has until 11:59 p.m. CT. The U.S. Tax Court is an important exception: it has held that electronically filed petitions must arrive by 11:59 p.m. Eastern Time, the court’s own zone. A petition sent at 11:30 p.m. Central on deadline day is actually 30 minutes late.
Commercial Trucking Logs
Under 49 CFR § 395.8, commercial drivers record hours of service using the time zone of their home terminal, not the zone they happen to be driving through.7eCFR. 49 CFR Part 395 – Hours of Service of Drivers A driver based in Chicago keeps every log on Central Time even on a run through Mountain or Pacific. Electronic logging devices are built to convert UTC to the home terminal’s time. The rule stops drivers from using zone crossings to stretch their allowable hours.
Who Sets the Boundaries and How They Change
The legal foundation is the Uniform Time Act of 1966, at 15 U.S.C. §§ 260–264. It gives the Secretary of Transportation authority to define and modify each zone’s boundary by official order.8Office of the Law Revision Counsel. 15 USC Chapter 6, Subchapter IX – Standard Time The two statutory factors are the “convenience of commerce” and the location of junction and division points used by interstate or foreign carriers.5Office of the Law Revision Counsel. 15 USC 261 – Zones for Standard Time; Interstate or Foreign Commerce
The Department of Transportation reads “convenience of commerce” broadly, covering commuting patterns, media markets, health care and school access, shipping destinations, and even which cell towers reach an area.9U.S. Department of Transportation. Procedure for Moving an Area from One Time Zone to Another A change that would cut a community off from the economic region it depends on tends not to survive review.
A local government that wants to switch zones petitions the Secretary of Transportation through the General Counsel in Washington. The request has to come from the highest political authority in the area (a governor or state legislature for a statewide move, a county commission or equivalent for a local one), with evidence covering commerce, commuting, media, transportation, and where residents actually go for work, school, and services. Preference surveys alone rarely carry a petition.
Opting Out of Daylight Saving Time
Under 15 U.S.C. § 260a, a state entirely within one time zone can exempt itself from daylight saving by state law, but the exemption has to cover the whole state and every subdivision. A state that spans more than one zone can exempt either the whole state or the part sitting inside a single zone.10Office of the Law Revision Counsel. 15 USC 260a – Advancement of Time or Changeover Dates
Only Arizona (except the Navajo Nation) and Hawaii have used that option. Five U.S. territories — American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands — also skip DST. No state in the Central zone has opted out, though nothing in the statute prevents one from doing so.
What the statute does not allow is permanent daylight saving time. States can lock themselves onto standard time, not the other way around. Several states have passed laws expressing a preference for year-round DST, but each is contingent on Congress changing federal law first. The Sunshine Protection Act, which would authorize permanent DST nationally, has been reintroduced repeatedly, most recently as H.R. 139 in January 2025, and remains stuck without a floor vote.11Congress.gov. HR 139 – 119th Congress (2025-2026) Sunshine Protection Act of 2025 Until Congress acts, any state hoping to stay on Central Daylight Time year-round is legally blocked from doing so.