In Germany the time of day is a matter of law. The Physikalisch-Technische Bundesanstalt, the federal institute of metrology in Braunschweig, is responsible for distributing the exact legal time. A long-wave transmitter at Mainflingen near Hanau broadcasts its signal, DCF77, about 2,000 kilometers. It sets radio clocks, station clocks and many clocks in industry. According to a 2007 report, the most accurate of the institute’s clocks deviates from an ideal clock by at most one millionth of a second in a year. After the clock change in October 2025, the institute said: Wir haben alles kontrolliert, es ging reibungslos. We checked everything, it went smoothly.