"UT" is an abbreviation for Universal Time, a time standard commonly used by astronomers. Observers of comets or meteor showers typically convert their time of observation to UT and then submit their observations to various organizations. These organizations can then compare observations by people from different states or countries to properly study the behaviour of a comet or a meteor shower.
      The Comets and Meteor Showers web site is a tool frequently used by amateur and professional astronomers and therefore, whenever possible, times are given in UT. For non-astronomers, conversion is fairly easy using the table below. All you need to know is your time zone. If your state or country enforces daylight savings time you will need to add an additional hour to the times below.