AskHistorians

The Romans had 12 day-hours and 12 night-hours. The first daylight hour began at sunrise. The last daylight hour ended at sunset. There were no minutes or seconds tracked, but this means that as the length of the day got longer/shorter the length of the Roman daylight hours were longer/shorter. E.G. The hour of what we think of as 2:00 pm might be ~80 minutes in summer and ~40 minutes in winter instead of always being 60 minutes.