The most populous country to use Central European Time is Germany.
Central European Time (CET) is set at UTC+01:00 and is used as standard time across much of Europe. Germany observes CET during the winter, then advances clocks to Central European Summer Time (CEST), UTC+02:00, during daylight saving time.
Germany’s population is larger than that of other major CET-using countries such as France, Italy, Poland, and Spain. Germany is also the most populous member state of the European Union, with roughly 84 million residents. France can cause confusion because metropolitan France uses CET in winter, while its overseas territories follow other time zones.
CET has historical roots in the railway era. A German railway organization introduced Central European Railway Time in 1891, helping coordinate train schedules across national borders. Today, the same UTC+01:00 standard links countries from Spain and France to Poland and Sweden, although their summer clock changes are governed by European daylight-saving rules.