In the graph below you see the time zone difference between Greenwich Mean Time and Central Standard Time. Drag the bubble to adjust the time and to see the corresponding time in the other time zone.
Greenwich Mean Time is the time zone of the 0 meridian, located in London, United Kingdom, including cities like London, Lisbon and Dublin (in the winter). Central Standard Time is the time zone of the central US and Canada, as well as most of Central America, with places like Winnipeg, Chicago, Dallas, Houston, Mexico City, San Jose and Panama City.
Usually it is preferable to schedule meetings in the afternoon for the person in GMT and before lunch for the person in CST.
GMT, or Greenwich Mean Time, is the zero when it comes to time zones – they are all counted from the zero meridian that runs through the village of Greenwich.
While both the UK and Portugal are officially on GMT you need to pay attention to whether they are actually observing it or are using their own. Britain in the summer for example use British Summer Time – which is different than GMT.
London, Lisbon, Dublin, Edinburgh
GMT does not observe DST as it is the zero hour time zone – it never changes.
Central Standard Time is the time zone of the central US and Canada, as well as Mexico and most of Central America. It is six hours behind UTC and is observed during the winter months. In the summer CST becomes CDT – Central Daylight Time. It is important to remember that not all locations in a given state or province necessarily use the time zone – make sure to check the situation for your exact location!
CST is observed in the US, Canada, Mexico and all of Central America (including Belize, Costa Rica, Guatemala, El Salvador, Nicaragua, Panama and Honduras). In the US it is only the states in the central parts that observes CST, from Wisconsin in the West to Tennessee in the East, and from Michigan in the North to Florida in the South. Similarly, only Canadian provinces in the middle of the country observe CST. With the exception of the North West corner, all of Mexico observes CST.
Mexico: México (including Mexico City), Oaxaca, Yucatán, San Luis Potosi, Chiapas and more.
Canada: Saskatchewan (only Creighton and Denare Beach), Manitoba and most ports of Ontario
US: Nebraska, Wisconsin, Alabama, Arkansas, Louisiana, Texas, Illinois to mention a few.
Most locations in Central Standard Time observe summer time between March and November, then calling it CDT – Central Daylight Time. It is always advisable to check the exact location (e.g. using our time zone converter) instead of relying on time zone abbreviations as there are sometimes exceptions, e.g. some states in the US are split between two time zones.