I had never heard of it before but I know what it means, and AI has spelled it out: 'Blue Monday refers specifically to the third Monday in January, though some variations place it on the second or fourth. In 2026, it lands on 19 January, coinciding with the current date and amplifying its relevance amid ongoing winter conditions. The notion of Blue Monday emerged in 2005 when Cliff Arnall, a former tutor at Cardiff University, calculated it using a formula that included weather conditions, debt levels, time elapsed since Christmas, failed resolutions, low motivation, and the urge to act. Arnall's work was commissioned by Sky Travel to promote holidays, positioning the day as ideal for booking trips to escape the gloom. Despite widespread criticism from scientists who call it pseudoscience, the term has stuck, appearing annually in media and social discussions. As Sky News explained in a X post, the day reflects a mix of post-holiday slump, financial pressures, and short daylight hours that can exacerbate low moods.'