Overview
- Media note the third Monday of January—January 19 in 2026—as the date commonly tagged as Blue Monday, though the designation is cultural rather than clinical.
- The concept originated with psychologist Cliff Arnall and a Sky Travel campaign that promoted a pseudo-mathematical formula never published or validated by peer review.
- Psychologists and health bodies reiterate there is no evidence for a universal "most sad" day and warn the trope can trivialize conditions like depression.
- Reporting highlights credible January mood drivers such as reduced daylight and cold in the Northern Hemisphere, post-holiday financial strain, routine resumption, and unmet resolutions.
- Guidance emphasizes sleep, exercise, daylight exposure, social connection, realistic goals, and seeking professional help when low mood is persistent or disabling.