The planet is divided into 24 time zones. This is so that the average solar time of each time zone is in accordance with the true solar time. When we travel east we move our watch forward and when we travel west we move our watch backward. Normally the difference between the time zones is always one full hour, so the minute remains the same. There are however some rare exceptions where the difference is 30 minutes and sometimes even 45 minutes. It also happens that some countries decide to change their time zone. This was the case of Venezuela, which for some years wanted to be half an hour ahead of its Colombian neighbor. This made worldtimers that had the Venezuelan capital, Caracas, engraved on their bezels or printed on their dials obsolete for some years. For the aviation world, regardless of where you are, we use exclusively the Greenwich Mean Time, whose abbreviation is GMT, which remains the same throughout the year without seasonal variations.