This public service is provided by the Time and Frequency Division of the National Institute of Standards and Technology (NIST). It uses the national time scale UTC(NIST) as its time reference.   This web site is intended as a time-of-day service only. It should not be used to measure frequency or time interval, nor should it be used to establish traceability to NIST. If the light/dark region looks incorrect, a click of reload *should* fix it. Otherwise there may be a problem in your browser with using javascript. To convert 24-hour time to 12 hour time, subtract 12 if the time is greater than 12. A toggle switch for this will probably be featured next time we rework the web page. For questions about a.m./p.m., noon/midnight and UTC, check our FAQ For sunrise/sunset information contact Astronomical Applications Web Page   To see the animated clock, be sure that java is enabled on your browser. In most cases, a new download of java will fix the animated clock. Otherwise, you can try a different browser.  Also, you may be behind a firewall and you will need to have your network administrator open port 8013 in order for it to work. Also, you can click on "Disable Java Animation" in order to see a static clock.     You can download software from NIST to use the Internet to automatically set your computer clock to the correct time using the Internet Time Service.     For a more detailed time zone map, look at our map of US time zones.   For time zone offsets around the world, please consult a world time zone map.   Please send any comments or questions to: timeinfo@boulder.nist.gov However, due to the volume of email we receive, we cannot always respond to each one individually.