Why our clocks lie about the length of a day

A vintage plough decorated for Plough Sunday
A vintage plough decorated for Plough Sunday

by Heather Elvidge

It was one of those sights that make you doubt what you’re seeing. In a Filey garden, last summer’s bedding marigolds were still alive, and what’s more they were in full bloom.

Yes, the plant was sheltered from the perishing wind, but still it’s remarkable. Maybe you have something equally odd happening in your garden.

In spite of some wild and stormy periods this winter has been generally mild. At least, it has so far. By now the seas around us have lost their stored warmth, and January sunlight is too weak to do much good. This old saying sums things up: “As the days lengthen, so does the cold strengthen.”

Some say the hardest winters are those that start around Twelfth Night. Certainly, we can rely on January to bring at least one cold snap. That doesn’t necessarily mean snow, but a good hard frost would be welcome, to kill off moulds that are flourishing in the damp soil. We’d rather have a chill now, and get it over with. Folklore says: “In January if the sun appear, March and April will pay full dear.”

For next month’s weather we have to look to last October. According to old lore, a mild October means the following February will be cold.

Finally, farmers who need to make silage or hay know the truth of this one: “If grass do grow in Janiveer, ‘twill grow the worse for all the year.”

January 12 is Plough Sunday, the day when a plough was taken to the parish church to be blessed before work resumed on the land. In pre-industrial communities people depended on a good harvest, and for them the plough was a symbol of life and prosperity.

Today, many churches hold special services to celebrate rural life and to pray for those who work the land. While plough parts are blessed at the altar, a tractor or in some places a pair of heavy horses, will be waiting outside the church.

Timeslip

Even on the dampest and gloomiest morning, things are stirring in the sodden earth. Spring bulbs can’t wait to poke their green shoots above the soil.

What are they thinking of? Aren’t the mornings darker than ever, even though the shortest day was before Christmas?

It’s true — the sun is as reluctant to rise as we are. But don’t blame our star; the fault lies with our timepieces.

Because of the earth’s path around the sun and the way the earth tilts on its axis, the exact length of a day varies. Most of our days are not 24 hours long. That figure is an average day length, taken across the year. Basically, our clocks are lying.

The difference between clock time and sun time is most obvious in December and January, when the clock eases ahead a bit more every day. By the time we are halfway through February, our clocks are in front of the sun by around 14 minutes.

Bring back sundials, I say, and then we’d have an excuse for hibernating in winter.