Definition

The time scale that is available from most broadcast time signals. It differs from INTERNATIONAL ATOMIC TIME by an integral number of seconds. UTC is maintained within 1 second of UT1 by the introduction of 1-second steps (leap seconds) when necessary, normally at the end of Decem­ber. DUT1, an approximation to the difference UT1 minus UTC, is transmitted in code on broadcast time sig­nals.