What is 18z, 00z, etc., or “why do meteorologists frequently use Z time?”
“Z” in this context is short for Zulu time, also commonly called “UTC” (Coordinated Universal Time) or “GMT” (Greenwich Mean Time). Using a 24-hour clock similar to military time, this is a time that is equivalent to the time in Greenwich, London during winter in the UK. Using Z time is convenient for occupations such as aviation and meteorology, where information is shared across large areas, and worrying about time zones becomes more cumbersome. For example, if we say in our discussion that “thunderstorms are expected to form between 21z and 23z,” and the time is currently 20z, the reader can know immediately that thunderstorms are expected to begin in one hour, rather than worrying about what time zone the reader or the author is in. In practice, since much of the world runs on local time, meteorologists do have to know how to convert between Z time and local time. In Utah, we are 6 hours behind Z time in the summer (MDT), and 7 hours behind Z time in the winter (MST). So, 18z is th
