Why is today, Blue Monday, considered to be the saddest day of the ...

Monday, 20 January 2025, 09:14

If your spirits are a little lower than usual this Monday, there is a mathematical explanation. Today (20 January) is Blue Monday, which is considered to be the saddest day of the year.

It has been marked annually on the third Monday of January since 2005. In that year, travel agency Sky Travel commissioned psychologist Cliff Arnall, a researcher at Cardiff University, to define the most depressing day of the year. The proposal had a business purpose: to try to sell more holidays to the public.

To reach his conclusion, Arnall used a formula that factored in the weather, debt and regret at the end of the holiday season: W+(Dd)] x TQ/M x NA. In it, W is “weather”, D is “debt” (debts acquired over the festive period), d is “monthly salary” multiplied by the time elapsed since Christmas (T, “time since Christmas'') and Q is the frustration for having broken New Year's resolutions while M is “low motivational level” and NA, the need to take action.

Blue Monday has been gaining popularity in recent years and it is common to see messages of encouragement circulating online and on social media to counteract what is supposed to be the 'officially' the saddest day of the year. Businesses also launch promotions, such as travel deals, to make the depressing day more bearable.