Blue Monday usually falls on the third Monday of January and is described as the most depressing day of the year in the Northern Hemisphere temperate areas.
This is because when daylight feels very short, Winter feels never-ending, and motivation can become low.
The concept of Blue Monday was coined in 2004 by former Cardiff University psychologist Cliff Arnall and was used in various publicity campaigns.
Arnell was invited by a PR company to find the best day for people to buy products for their summer holidays.
How “Blue January” became a marketing campaign
Based on his findings, the PR company behind the study went on to use the term “Blue January” in a publicity campaign for Sky Travel.
Cliff Arnall analysed several variables, including gloomy weather and lack of sunlight, debt accumulated over Christmas, the time left until payday, failed New Year’s resolutions, and low motivation and productivity levels.
Dr Arnall even created a formula to calculate the exact date of “Blue January”:
[W + (D − d)] × TQ / M × NA
Where W represents weather, D is debt, d is monthly salary, T is time since Christmas, Q is time since failing New Year’s resolutions, M is motivation level, and NA is the need to take action.
READ MORE: Ten ways to stick to your digital detox in 2026
But is it science?
Dr. Arnall received heavy criticism from the medical community, which claimed that there is no scientific evidence that proves that a specific day can be universally the saddest.
One of the missing points of his problematic concept is that it does not take into account complex human emotions, which are unique and individual.
Cliff Arnall has since then refuted this theory, calling it useless and dangerous, encouraging people to “refute the whole concept.”
In an interview with The Telegraph, Dr. Arnall said that the Blue Monday theory became “a self-fulfilling prophecy” – where we believe that we are going to feel sad, so we adopt behaviours that will reinforce that feeling.
Is there a bright side?
In 2018, Arnall told a reporter at the Independent newspaper that it was “never his intention to make the day sound negative”, but rather “to inspire people to take action and make bold life decisions”.
Even though this is more of a symbolic label, mental health advocacy groups, schools, employers and charities have used Blue Monday to promote open conversations about emotional wellbeing, promote self-care and reduce stigma around mental health.
For some, mental health struggles can be enhanced during winter (SAD – seasonal affective disorder), for others, it might be social isolation or financial stress.
We could view Blue Monday not as a bad day, but as an opportunity to acknowledge that emotional well-being deserves attention.
A reminder to ask, listen and act with empathy to the people around us.
READ NEXT: Dry January: What it is and why it matters
Adam Peaker 
Eleni Poulios 
Andre Alfonso R. Gutierrez