Because this is a Leap Year, February had an extra day Monday — Feb. 29 — so it took a day longer on the calendar to get to today, March 1, than it did the three previous years.

You will recall how Leap Year is when the calendar is adjusted because it takes 365 and 1/4 days to orbit the sun, so every four years we allow for those four extra quarter days by adding a day to February. I read that it’s actually 365.24219 days that it takes the Earth to orbit the sun but they round it to a quarter day.

The practice of adding a day to the calendar to catch up for those quarter days reportedly dates back to 45 B.C. when Julius Caesar ordered an extra day be added to the calendar every four years.

I’m impressed that more than 2,000 years ago they were smart enough to figure out the Earth needed that extra quarter day to orbit the sun.

But I read an article on CNN’s website that said in 1582 the rounding of 365.24219 to .25 was determined to have caused the calendar to be off by 10 days, even with the one extra day every four years.

So Pope Gregory XIII saw to the establishment of what was called the Gregorian calendar and set Feb. 29 as the official day to adjust for the extra day needed in a Leap Year.

I read elsewhere that adding a day every four years still doesn’t really keep things straight because the 0.24219 is a bit short of .25. Over four centuries, the adding of a day every Leap Year creates about three extra days, so every 400 years three Leap Years aren’t used so as to eliminate the extra days.

They do this by not having a Feb. 29 in the three century years that cannot be evenly divided by 400. This happened in 2000 and will happen again in 2400.

I remember this being discussed back in 2000. I doubt I’ll be around for the next adjustment in 2400.

My mother-in-law Teo Hentz, now deceased, was born on Feb. 29. Most years as I recall she celebrated her birthday on March 1, I think not wanting to observe Feb. 28 for a birthday in the years where there was not a Feb. 29. I don’t think she wanted to claim being a day older any sooner than she had to.

It was always a bit odd to celebrate her birthday not only on a different day than that on which she was actually born but also in a different month.

I remember one Leap Year when there was a Feb. 29 so she was going to celebrate her actual birthday. Someone figured out this particular birthday was technically her 16th — only the 16th time since she’d been born her birthday appeared on the calendar.

I know I got some odd looks when I shared with others how my mother-in-law at that time was celebrating her 16th birthday. She’d been around 64 years then but indeed, it was only birthday number 16.

Hope you appreciated you got an extra day Monday.

WILL CHAPMAN is publisher of The Daily Iberian.