The weather report updated at 1500 AST would be 3:00 pm report. What is the 1900 GMT that follows?
GMT means Greenwich Mean Time, which is the time of the Greenwich Astronomic Observatory. The observatory is located in London, England where the longitude is 0 degrees. In this case, to calculate your local time from GMT time, subtract 4 hours. GMT does not take into account daylight savings time so when applicable, it must be factored in. GMT is also known as Zulu (Z) time and Coordinated Universal Time (UTC).