As if any Monday in January weren't bad enough, Blue Monday, an ill-reputed date dubbed "the most depressing day of the year," should really put you in a mood.

While there has been some confusion over exactly which day Blue Monday falls on in 2013, the official date is January 21.

The theory of Blue Monday dates back to 2005, when UK psychologist Cliff Arnall created an elaborate mathematical formula to calculate the most miserable day of the year.

Thanks to the day's perfect storm of drab weather, holiday bills, and wrecked New Year's resolutions, motivational levels, the idea goes, hit an all-time low.

The result: feeling depressed, being inactive, and eating too many carbohydrates.

But of course whether there is any truth to the theory is a source of contention, since Arnall created the formula as part of a marketing campaign for Sky Travel, a travel company.

Still, whether or not your dreary winter mood will peak on this particular day, if you are prone to winter blues, there are a few mood boosters you can try short of a vacation somewhere balmy -- actually the Mayo Clinic recommends that, if you can afford it.

A recent survey of 2,000 Brits by Anglian Home Improvements in the UK found that sitting by a window or going outside for a stroll -- even in dim winter light -- boosted the blues.

Alternatively you could try light therapy. While there are no official guidelines, such as how long you should sit under a light box, be sure to use a specialized light box that mimics outdoor light.

Experts also recommend exercise -- winter sports such as skiing and snowshoeing can kill two birds with one stone (outdoor light, exercise). If temperatures are too frigid, opt for the gym or work out at home with videos, DVDs, or fitness apps.

Content site Hubpages adds a few recommendations to the mix: Go to bed early and wake up before sunrise, to maximize your exposure to daylight. Also, go outside at midday, and don't drink caffeine after 2 pm, to help you get to bed earlier.