February - Patterns

Patterns

February starts on the same day of the week as both March and November in common years, and August in leap years.

Having only 28 days in common years, it is the only month of the year that can pass without a single full moon. It is also the only month of the calendar that once every six years and twice every 11 years, will have only four full 7-day weeks. Where the first day of the month starts on a Monday and the last day ends on a Sunday, this was observed in 2010 and can be traced back 11 years to 1999, 6 years back to 1993, 11 years back to 1982, 11 years back to 1971 and 6 years back to 1965; and so on twice 11 years consecutively and once six years either forward into the future or back into the past. This works unless the pattern is broken by a skipped leap year, but no leap year has been skipped since 1900 and no others will be skipped until 2100. (Years that are evenly divisible by 100 are not leap years, unless they are also evenly divisible by 400, in which case they are leap years.) A year of this kind would be a common year starting on Friday. It cannot happen in a leap year.