Late tonight, or first thing tomorrow morning to be precise, the hour will go forward.
It means everyone either gets an hour less in bed or else they are running an hour late all day tomorrow, and perhaps into Monday as well.
But for most people there is a consolation.
Again and again at this time of year, Ulster people can be heard saying: “Aren’t the days getting longer?” or “Have you noticed the stretch in the evenings?” or something similar.
Then, suddenly, in the weeks before and after the hour change in late March, we go from it getting dark at not long after 6pm to almost 8pm. The change becomes the welcome sign that summer is close, after a long, winter.
Being as far north as we are in this Province — in the mid 50s latitude — means that we have seriously dark winters and seriously light summmers. You only have to travel about 500 miles north of Portrush to reach that part of the globe that experiences 24 hours darkness in December and 24 hours of daylight in June.
In Northern Ireland, we get a taste of that: our shortest day is only properly light from 9am to not long after 3pm, and our longest day is bright almost as early as 4am until nearly 11pm.
For this reason, daylight has, and has always had, a particularly significant impact on our daily lives here.
At Newgrange, near Drogheda, Neolithic farmers 5,000 years ago held elaborate celebrations to mark the shortest day of year, because it meant the return of daylight after the bleak days of November and early December.
There is growing debate about whether British Summer Time should be adopted year round in the UK so that we have longer evenings for 12 months. It is the Celtic fringes that are holding that back: it would mean sunrise of almost 10am in mid December in Northern Ireland and parts of Scotland.
The debate will rumble on. Unless and until there is such a reform, the six-monthly ritual of changing clocks will remain fixtures in the calendar that leave an imprint on our psyches.