Overview
- January 19, 2026 marks this year’s so‑called Blue Monday, the third Monday in January often labeled the ‘saddest day.’
- Reporters trace the label to Cliff Arnall’s 2005 equation created for Sky Travel, which scientists dismiss for lacking measurable units and rigor.
- The University of Cardiff has long clarified that Arnall only briefly held a part‑time role, and Arnall later distanced himself from the formula.
- Experts distinguish the myth from genuine seasonal mood changes linked to reduced daylight, lower vitamin D production and serotonin shifts.
- Guidance emphasizes daylight exposure, outdoor activity, light therapy and vitamin D, plus social contact and realistic goals, with warnings not to trivialize clinical depression and German helplines listed for support.