Time Zone:Central Daylight Time, CDT
UTC offset:UTC -5:00
Time Zone Abbreviation:CDT
History and Participating Locations
During the summer months, certain U.S. States within the Central Standard Time zone switch to a different time zone called Central Daylight Time as a part of Daylight Saving Time. This alternate time zone is 5 hours behind Coordinated Universal Time (UTC). It is used exclusively in North America.
In the winter, the clocks go back to CST time which is six hour behind UTC. Join us as we examine which states and locations follow this time zone during the summer and switch back during the winter. We will also examine the practice of Daylight Saving Time in the United States exclusively and why some states in this time zone are hoping to have it abolished.
Where is CDT Observed/Other Time Zones in This Offset
CDT is observed in the following United States:
- Florida - North-West parts: Calhoun, Escambia, Holmes, Jackson, Oakaloose, Santa Rosa, Walton, Washington, and northern Gulf county
- Indiana - these few north-western counties near Chicago (Lake, Porter, La Porte, Newton, Jasper, Starke) and these south-western counties in Indiana near Evansville
- Kansas - except these western counties: Greeley, Hamilton, Sherman, Wallace
- Kentucky - Western part: Adair, Allen, Ballard, Barren, Breckinridge, Butler, Caldwell, Calloway, Carlisle, Christian, Clinton, Crittenden, Cumberland, Daviess, Edmonson, Fulton, Graves, Grayson, Green, Hansock, Hart, Henderson, Hickman, Hopkins, Livingston, Logan, Lyon, Marshall, McCracken, McLean, Metcalfe, Monroe, Muhlenberg, Ohio, Rusell, Simpson, Todd, Trigg, Union, Warren, and Webster counties
- Michigan - A few western counties: Dickinson, Gogebic, Iron, and Menominee
- Nebraska - Eastern parts, all except Arthur, Banner, Box Butte, Chase, Cheyenne, Dawes, Deuel, Dundy, Garden, Grant, Hooker, Keith, Kimball, Morrill, Perkins, Scotts Bluff, Sheridan, and Sioux counties which are on MST/MDT
- North Dakota - North and Eastern parts: counties of Barnes, Benson, Bottineau, Burke, Burleigh, Cass, Cavalier, Dickey, Divide, Eddy, Emmons, Foster, Grand Forks, Griggs, Kidder, Lamoure, Logan, McHenry, McIntosh, McLean, Mountrail, Nelson, Oliver, Pembina, Pierce, Ramsey, Ransom, Renville, Richland, Rolette, Sargent, Sheridan, Steele, Stutsman, Towner, Traill, Walsh, Ward, Wells, Williams and northern parts of McKenzie and Dunn, Morton and Fort Yates in Sioux
- South Dakota - Eastern parts: counties of Aurora, Beadle, Bon Homme, Brookings, Brown, Brule, Buffalo, Campbell, Charles Mix, Clark, Clay, Codington, Davison, Day, Deuel, Douglas, Edmunds, Faulk, Grant, Gregory, Hamlin, Hand, Hanson, Hughes, Hutchinson, Hyde, Jerauld, Kingsbury, Lake, Lincoln, Lyman, Marshall, McCook, McPherson, Miner, Minnehaha, Moody, Potter, Roberts, Spink, Sanborn, Sully, Tripp, Turner, Union, Yankton, Walworth and eastern parts of Jones and Stanley
- Tennessee - Western part: counties of Bedford, Benton, Bledsoe, Cannon, Carroll, Cheatham, Chester, Clay, Coffee, Crockett, Cumberland, Davidson, Decatur, DeKalb, Dickson, Dyer, Fayette, Fentress, Franklin, Gibson, Giles, Grundy, Hardeman, Hardin, Haywood, Henderson, Henry, Hickman, Houston, Humphreys, Jackson, Lake, Lauderdale, Lawrence, Lewis, Lincoln, McNairy, Macon, Madison, Marion, Marshall, Maury, Montgomery, Moore, Obion, Overton, Perry, Pickett, Putnam, Robertson, Rutherford, Sequatchie, Shelby, Smith, Stewart, Sumner, Tipton, Trusdale, Van Buren, Warren, Wayne Weakley, White, Willamson, Wilson
- Texas - All, but a few counties in west
There are a few Canadian provinces that use CDT in the summer and CST in the winter:
- Ontario - most parts west of 90 West, parts on the east side are on EST/EDT
- Sakatchewan - Specifically Creighton and Denare Beach
The Following Mexican States use CDT in the summer:
- Distrito Federal
- Nuevo León
- Quintana Roo
- San Luis Potosí
There are also several other time zones that have the same offset from UTC as CDT, but they have different names. They are as follows:
- ACT - Acre Time -
This zone is used in South America, primarily in the Brazilian states of Acre and the Amazonas
- COT - Colombia Time
This zone has the same offset as EST, but is used only in the country of Colombia in South America.
- CST - Cuba Standard Time
This zone is exclusive to the country of Cuba. During the summer months Cuba Daylight Time is followed (CDT).
- EASST - Easter Island Summer Time
This time zone only falls into UTC -5:00 when used on Easter Island and Rapa Nui in Chile during the summer months.
- ECT - Ecuador Time
This time zone is used throughout the year only in Ecuador with the exception of the Galapagos Islands.
- PET - Peru Time
This time zone falls into the same offset and is used in the country of Peru.
- R - Romeo Time Zone
This is a military time zone used by aircraft over the sea between the longitudes of 82.5 degrees West and 67.5 degrees West.
The Practice of Daylight Saving Time in the United States
We all know the concept of Daylight Saving Time as a practice in the United States where the clocks are moved forward by one hour during the summer and then back to the originally time in the winter. The result of this time change is more sunlight during the evening hours of the summer. Most of the U.S. States observe DST except for Hawaii and Arizona (with the exception of the indigenous Navajo Nation).
The common mnemonic for moving the clocks is expressed as “spring forward and fall back” which calls to mind the moving forward of an hour in spring and moving back an hour in the fall. These respective times fall within the months of March and November.
The Standard Time Act of 1918 was modified by the Uniform Time Act of 1966 to require a regulation issued by the Department of Transportation before a state can move from one time zone to another. Under this new legislation, the governor or state representative may submit the required inquiry for the entire state or just a part of it.
Moving an area’s time zone is decided based on the convenience of commerce, shipment, television and radio broadcasts, schools, businesses, places of worship, railroads, bus stations, airports, and many other factors in a state or county’s economy. After a public hearing, once comments have been made by the people who will be affected by the change, everything is reviewed. If the Secretary of the DOT approves the change, it is usually made at the next switch to or from DST.
Another aspect of the Uniform Time Act dictates that the process of moving an area onto or off of DST in general can only be done through legal action at the state level. This process varies from state-to-state and is obtained from the state’s legislative office. States can be exempt from DST but if they observe the practice, they must abide by federal laws.
Examples of DST Observances in the United States
The state of Alaska observes DST and due to the high latitude, it has almost round-the-lock sunlight during summer. Because of this, many people believe that the practice is a nuisance. The mainland’s single time zone is another issue for natives as the civil time and solar time are not at all in alignment. A bill was passed by state senator Ana MacKinnon to end DST, and the next step is for the House to consider the proposal.
Arizona observed DST in 1967 in accordance with the Uniform Time Act, but the state took steps to become exempt the following year and DST has not be observed since. The reason for this is due to the state’s energy consumption conversation. Since Phoenix and Tucson are some of the hottest US metropolitan areas, extra sunlight during the summer will skyrocket energy consumption and overall costs.
From the years 1970 to 2006, most of Indiana was in the Eastern Time Zone and did not observe DST. In April of 2006 though, eight counties in the west part of the state were shifted into the Central Standard Time zone and it was then that the state started to observe DST and move into the CDT zone during the summer. Currently there are 12 counties observing CDT during the summer and 80 counties observing EDT because of their time zone.
The Republican Representative of Tennessee, Curry Todd has sponsored a bill that would implement a permanent Daylight Saving Time in the state. The problem with an idea like this is that it would require the federal government to amend the Uniform Time Act to allow such a scenario. The act specifies specific times of the year to observe DST, causing the issue with this concept. The only other alternative would be to obtain approval from the DOT to move the state to another time zone.
The subject of Daylight Saving Time has been a hot button topic as of late and will only continue to grow as the practice become more and more divisive. There are arguments to be made on both sides of the equation. Some believe the practice is dated, others think it’s a good thing to have implemented.
For as long as it exists, there will be a Central Daylight Time zone to occupy those states during the summer months when they move their clocks forward into another offset of UTC.