What is Blue Monday and why is it ‘the most depressing day’ of the year …

The first Blue Monday was January 24, 2005, after Dr Cliff Arnall, a tutor at Cardiff University’s Centre for Lifelong Learning, was asked to work out the most depressing day of the year. The press release labelled Blue Monday was then released by Sky Travel to encourage people to buy holiday trips but has since become an annual event.

https://www.the-sun.com/news/171804/blue-monday-depressing/