Divorce lawyers in both the U.S. and the United Kingdom tend to batten down the hatches at the end of December, bracing for the new year and what it means for business. The first Monday after New Year's Day, called Divorce Day or Blue Monday, tends to bring an influx of clients who want to initiate divorces. The tide usually continues through January and into spring.

Divorce Day Statistics

Divorce Day comes by its notoriety honestly -- MarketWatch says that divorce filings increase by a third in the month of January. The Legal Services Commission says it starts on the first Monday after the kids go back to school. Divorce papers may not be filed on the first Monday, but spouses start meeting with lawyers and laying the groundwork to part ways. Perhaps not coincidentally, MarketWatch also reports that activity on the dating website Match.com was at its highest on the Monday after New Year's Day in 2015 as well.

The Reasons Behind the Rush

So why do so many spouses storm the gates of marital freedom within days of that last champagne toast? One of MarketWatch's experts claims it's because they hang in there for one last "normal" holiday for the sake of the kids. They may be ready to file for divorce in autumn, but if they do so around Thanksgiving, they'll end up having to serve their soon-to-be exes – and by extension, the kids and in-laws – with divorce papers at mid-Hanukkah or just as Santa is trying to squeeze his way down the chimney. Then there are those New Year's resolutions. When spouses have been unhappy all year, the holiday tradition might be just the impetus they need to finally pick up the phone and call a divorce lawyer.

Tax Issues

Divorces can take several months from the filing date to the final decree. Some states have statutory waiting periods, and some divorces are just plain ugly so spouses have to negotiate through a web of time-consuming pretrial motions and other court appearances. If you file for divorce in January, it makes it more likely that you'll be able to wrap up the ordeal by Dec. 31. And if you're legally single on Dec. 31, the Internal Revenue Service says you're considered unmarried for the whole tax year – you don't have to file a joint return with your ex, or a separate married return.

Maybe It's Not About the Marriage

Upbeat Drinks, a research team in England, suggests that Divorce Day might have less to do with marriages than with people's overall unhappiness at this time of year. The group claims it filtered more than 2 million social media posts over a two-year period and found that one day of the year is notorious for negativity -- you guessed it, the Monday after New Year's. It should be noted, however, that people were as inclined to complain about their jobs or the weather as they were about their marriages.