2016 is a leap year, which means we all get a full extra calendar day today! For the most part, leap years are an interesting quirk (as well as a frequent source of jokes about 4-year olds getting driver's licences and 16-year-olds retiring), but legally speaking, this extra day in February can be a bit of a headache.
Leap year legislation has a long and storied history that dates back to at least 1236 A.D., when King Henry III of England issued De Anno Bissextili (the Statute of the Leap Year), which stated that "the Day of the leap Year, and the day before shall be holden for one Day". Under this statute, the month of February in leap years functionally had 27 regular 24-hour days, as well as one 48-hour day.
The year 1236 may seem like ancient history, but King Henry III's leap year statute was grandfathered into a number of other legal systems, including ones in both Canada and America. The statute was cited as recently as 2013 in the Iowa Court of Appeals in a decision about the timeliness of a February 29th filing. To this day, in both countries, February 28th and 29th are regularly considered to be one day for many legal purposes.
As a result, one leap year issue that frequently arises is the impact of the additional working day on an employee's paycheque. For salaried employees who are paid on a monthly or bi-monthly schedule, the CBC points out that "employees under this arrangement are essentially volunteering their services [on Feb. 29th]." So it's no surprise that leap years have led to union grievances about pay calculations, like this 2014 arbitration involving the Calgary Police Association "over whether a year involves 2080 or 2088 working hours".
The 2008 Rahman v. Canada immigration appeal was another very interesting Canadian leap year test case. A little bit of citizenship background: The version of the Citizenship Act that was in force in 2008 required that permanent residents accumulate "three years of residence in Canada" over a four-year period in order to be eligible for citizenship. Based on a 365-day year, that requirement worked out to 1,095 days of residence.
But not all years have 365 days. In Rahman v. Canada, the applicant's citizenship application was denied because he was exactly one day short of the physical presence requirement. The applicant appealed, arguing that he actually was in Canada for the mandatory 1,095 days, but that the Citizenship Judge had made a calculation error because "she did not count the leap day (February 29, 2004) towards the Applicant's physical presence". However, the Minister of Citizenship and Immigration argued that the judge had made the right call since the text of the Citizenship Act referred specifically to years and not days, and that the Ministry determined "whether the three year statutory requirement has been met by calculating the number of days present other than leap days".
Unfortunately for the applicant, the judge agreed with the Ministry's argument. Even though the applicant was physically present for 1,095 days, only 1,094 of them mattered to the court. He might have been physically present in Canada on February 29th, but legally, it didn't count.
In modern times, leap years usually don't pose too many significant legal issues, but the devil can be in the details. As a result, many Canadian Acts that deal with specific dates or deadlines have explicit provisions for leap years. For instance, the BC Motor Vehicle Act specifically defines March 1st as the legal "birthday" for leap-year babies in years without a February 29th, while the Ontario Legislation Act sets out that "the anniversary of an event that took place on February 29 falls on February 28, except in a leap year."