About Blue Monday
Claimed to be the most depressing day of the year, Blue Monday was first referenced in a press release by Sky Travel in 2005.
The company, eager to calculate when people tend to book their holidays, commissioned Dr Cliff Arnal, a British psychologist, to create a formula to do just that.
Arnal claimed that his formula, which supposedly pinpointed the most depressing time of the year, could predict when people would book trips to sunny, happy, holiday destinations.
His theory took into account seasonal weather, the time that had elapsed since Christmas, levels of personal debt, and monthly income.
Adding all those factors together, Arnal argued that the third Monday in January was the most depressing day of the year - and therefore the day when high numbers of people would book their tropical escapes.