Jan. 24 is the worst day of the year, with bad weather, debt, fading Christmas memories, failed resolutions and a lack of motivation combining to depress people.

This is the contention of Cliff Arnalls, a part-time university tutor in Wales.

The Cardiff university instructor has come up with a formula to measure the winter-time blues, the BBC reported.

According to Dr. Arnalls' equation, 1/8W+(D-d) 3/8xTQ MxNA, misery peaks next Monday, Jan. 24, a month after Christmas.

JANUARY BLUES DAY FORMULA
1/8W+(D-d) 3/8xTQ MxNA. Where: W: Weather D: Debt d: Money due in January pay T: Time since Christmas Q: Time since failed quit attempt M: General motivational levels NA: The need to take action
Arnalls calculated the effects of cold, wet – in the case of Britain – and dark January weather after the cosiness of Christmas coupled with extra spending in the sales.

Any energy from the holidays had worn off by the third week of January, he said.

By Monday, most people will have fallen off the wagon or abandoned the nicotine patches as they fail to keep New Year's resolutions.

That compounded a sense of failure and knocked confidence needed to get through January.

The fact that the most depressing day fell on a Monday was not planned but a coincidence, Arnalls said.