Blue Monday (date)



Blue Monday is a name given to a day in January (typically the third Monday of the month) reported to be the most depressing day of the year for countries in the Northern Hemisphere. The concept was first publicised as part of a 2005 press release from holiday company Sky Travel, which claimed to have calculated the date using an equation.

The idea is considered pseudoscience, with its formula derided by scientists as nonsensical.

History
This date was published in a press release under the name of Cliff Arnall, at the time a tutor at the Centre for Lifelong Learning, a Further Education centre attached to Cardiff University. Guardian columnist Dr. Ben Goldacre reported that the press release was delivered substantially pre-written to a number of academics by public relations agency Porter Novelli, who offered them money to put their names to it. The Guardian later printed a statement from Cardiff University distancing themselves from Arnall: "Cardiff University has asked us to point out that Cliff Arnall... was a former part-time tutor at the university but left in February."

Variations of the story have been repeatedly reused by other companies in press releases, with 2014 seeing Blue Monday invoked by legal firms and retailers of bottled water and alcoholic drinks. Some versions of the story purport to analyse trends in social media posts to calculate the date.

Date
The date is generally reported as falling on the third Monday in January, but also on the second or fourth Monday, or the Monday of the last full week of January. The first such date declared was 24 January in 2005 as part of a Sky Travel press release.

Calculation
Arnall has said the date was devised to help a travel company to "analyze when people book holidays and holiday trends" and used many factors, including: weather conditions, debt level (the difference between debt accumulated and our ability to pay), time since Christmas, time since failing our new year’s resolutions, low motivational levels and feeling of a need to take action. One equation used by Arnall in 2006 was:
 * $$\frac{(C \times R \times ZZ)}{((Tt + D) \times St)} + (P \times Pr)>400$$

where Tt = travel time; D = delays; C = time spent on cultural activities; R = time spent relaxing; ZZ = time spent sleeping; St = time spent in a state of stress; P = time spent packing; Pr = time spent in preparation. Units of measurement are not defined.

The 2005 press release and a 2009 press release used a different formula:


 * $$\frac{[W + (D-d)] \times T^Q}{M \times N_a}$$

where W=weather, D=debt, d=monthly salary, T=time since Christmas, Q=time since failing our new year’s resolutions, M=low motivational levels, and Na=the feeling of a need to take action. Again, no units were defined.

Ben Goldacre has observed that the equations "fail even to make mathematical sense on their own terms", pointing out that under Arnall's original equation, packing for ten hours and preparing for 40 will always guarantee a good holiday, and that "you can have an infinitely good weekend by staying at home and cutting your travel time to zero". Dean Burnett, a neuroscientist who has worked in the psychology department of Cardiff University, has described the work as "farcical", with "nonsensical measurements".

Happiest day
Arnall also says, in a press release commissioned by Wall's ice cream, that he has calculated the happiest day of the year—in 2005, 24 June, in 2006, 23 June, in 2007, 20 June in 2009, 19 June, and in 2010, 18 June. So far, this date has fallen close to Midsummer in the Northern Hemisphere (June 21 to 24).