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Jim Stump
 on February 28, 2020

The Theology of Leap Years

It’s a leap year. What does this mean? Why did God choose to create a year ratio that needs so much calculation and explanation?


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This Thursday is Leap Year Day.

I’ve always had a fascination with how we as a species understand and mark the passage of time, and I’ve never felt that we’ve gotten this one right. Adding in an extra day in February every four years or so always seems so inelegant and quintessentially ad hoc. Surely there must be a better way.

When I was in elementary school, there was a kid on my bus who was born on February 29. We’d joke with him about not having had three birthdays yet, and not being able to vote until he was a grandfather. I’ve lost touch with him, and I don’t think I know any “leaplings” now (please correct me if I’m wrong about this). I doubt that it has a major effect on one’s life.

Undoubtedly there are bigger concerns I should have (like why we’re still using qwerty keyboards!), but it bothers me that some of the ways we look to nature to keep track of things don’t quite sync up.

So what’s the problem?

The time it takes Earth to go around the sun—our year—is not perfectly divisible by the time it takes Earth to spin around once on its axis—our day. Let’s pretend our sun is stationary in space (it’s not, but it doesn’t affect this). Then we could say a year begins and ends whenever Earth gets to the same spot in space during its orbit of the sun. But on a non-leap year when the ball drops in Times Square at midnight on New Year’s Day, Earth still has about six more hours until it gets to the same spot it was at midnight on the previous New Year’s Day. If we just kept using a 365 day calendar to mark a year, we’d be celebrating the New Year six hours earlier every year. In a hundred years that would add up to 25 days earlier, and in six hundred years we’d be celebrating Christmas during the peak of summer!

So, every four years we toss in February 29 to make up for that six hours per year and to keep Christmas where it belongs among the seasons (with apologies to our friends in the antipodes).

I suppose that would be fine, if that’s all we had to do. But, of course, it is more complicated than that.

Because it turns out that it’s not exactly six hours more each year for Earth to reach the starting spot in orbit. It’s more like five hours and forty-nine minutes. So we can’t just keep doing leap year every four years, or that eleven minutes would eventually throw things off. So we skip leap years when it is the turn of the century like 1800 and 1900… but that’s not quite right either, because there was a February 29, 2000. Therefore the official rules for leap year according to the Gregorian Calendar are:

A year has February 29th if that year is divisible by 4, unless it is also divisible by 100—then it doesn’t… unless it is also divisible by 400—then it does.

Or more formally (the former logic professor in me can’t help doing this):

A year is designated as a Leap Year, if and only if the following conditions are both satisfied:

    1. The year is divisible by 4
    2. It is not the case that the year is divisible by 100 and not 400

As perfect and precise as this sounds, it still doesn’t match up to reality. So the International Earth Rotation and Reference Systems Service tosses in a leap second at the end of December or the end of June when needed. There have been 28 of these since the first one in January of 1972 (and in case you’re planning something very time-sensitive, they have already announced there will be no leap second this June).

Theological Implications to Leap Year?

For those who view God as a kind of cosmic engineer, all this seems like a problem. Why wouldn’t God design things so these natural timepieces sync up better for us? (And I’m not even getting into the lunar month and its 29.5 day cycle of phases based on its 27.32 days to orbit Earth!) Some people might use this to question God’s competence or wisdom.

There is an opposite theological reaction that is equally problematic: if God isn’t determining every detail, do we have to say God is uninvolved and unconcerned? The deists claim that God started things up, but then went off somewhere and let things go without any further interest or concern about what it might mean for us and our calendar.

I think a healthier perspective is to say that God intentionally created things so that they would have a role to play in the ongoing drama of creation. Charles Kingsley was a priest in the Church of England and a contemporary (and friend) of Charles Darwin. In 1863, he published a fairytale called The Water-Babies in which the main character appears to drown, but is transformed into a water-baby and given a proper education by the creatures he encounters. A whale points him to Mother Carey, a creator figure, saying, “There she sits making old beasts into new all the year round.” But when the boy got to her and asked about making things, she replied,

“Know, silly child, that any one can make things, if they will take time and trouble enough: but it is not every one who, like me, can make things make themselves.”

There are some parameters required for a world that participates in its own making, and these appear to have been very precisely fine-tuned. And I can’t believe that God is unconcerned about what his creation is doing. Rather, like a parent who watches the children create, God delights in what we’re doing. Of course he could step in and do it better, just like we might make a better Lego machine or paint a better picture than our three-year-olds. But where’s the fun in that? (On this theme, I strongly recommend reading Bethany Sollereder’s article, Toward a Theology of Astronaut Beavers.)

The solar system settled in on an inelegant ratio between Earth’s days and years—kind of like a kid drawing a human figure, with various parts out of proportion. In our attempt to make sense of this, we humans have settled in on the Gregorian Calendar, which has the feel of a Mr. Potato Head…put together without all the proper parts… by a committee. It might be frustrating to us that we can’t get it exactly right, but from the parent’s perspective, it’s kind of cute.

So take this week’s Leap Day and try to think of it from God’s perspective—a parent looking at what his kids have come up with. I bet on Leap Day God will be proudly putting us up on the refrigerator in the Heavenly Council’s break room, and saying, “Look at what my creation made. Isn’t this awesome?!”

Of course, exactly when on Leap Day God will do this is another question… don’t get me started on time zones!

This article was originally published in 2020; updated February 26, 2024.

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About the author

Jim Stump

Jim Stump

Jim Stump is Vice President of Programs at BioLogos. He oversees the editorial team, participates in strategic planning, and hosts the podcast, Language of God. Jim also writes and speaks on behalf of BioLogos. He has a PhD in philosophy and was formerly a professor and academic administrator. His earlier books include, Four Views on Creation, Evolution, and Intelligent Design; Science and Christianity: An Introduction to the Issues; and How I Changed My Mind about Evolution. Most recently he has published, The Sacred Chain: How Understanding Evolutions Leads to Deeper Faith (HarperOne, 2024). You can email Jim Stump at or follow him on Substack.