How long is the 45th parallel?

The 45th Parallel: More Than Just a Halfway Point

Ever heard of the 45th parallel north? It’s that imaginary line circling our planet, sitting pretty at 45 degrees north of the equator. Think of it as the Earth’s belt, sort of halfway between the North Pole and the equator. Though, spoiler alert, it’s not quite the true halfway point, but we’ll get to that in a bit. The big question is: how long is this global loop?

Crunching the Numbers: It’s Not a Simple Circle

Turns out, figuring out the 45th parallel’s length isn’t as easy as dusting off your old geometry textbook. You can’t just use the Earth’s regular circumference. Why? Because our planet’s a bit lumpy! It’s an “oblate spheroid,” which is just a fancy way of saying it bulges at the equator and squishes at the poles. Imagine squeezing a beach ball – that’s kind of what’s going on.

Now, if we pretended Earth was a perfect sphere, we could take its average circumference (around 24,901 miles or 40,075 kilometers) and multiply it by the cosine of 45 degrees (roughly 0.7071). Boom, you’d have an estimate. But, and it’s a big but, that’s not the whole story.

For a truly accurate measurement, you need to factor in that whole “oblate spheroid” thing. Using something called the WGS84 ellipsoid – basically a super-detailed mathematical model of Earth – the 45th parallel clocks in at roughly 28,385 kilometers, or about 17,638 miles. That’s a pretty long walk!

Halfway? Not Exactly…

You’ve probably seen those signs proclaiming the 45th parallel as the “halfway point.” It’s a nice thought, and a great photo op, but it’s not entirely true. Remember that equatorial bulge? It nudges the real halfway point about 16 kilometers (or 9.9 miles) north of the 45th. So, while the signs are a fun landmark, they’re bending the truth a little.

A World Tour on the 45th

What’s really cool is where this imaginary line actually goes. The 45th parallel cuts through some seriously diverse landscapes. Here in North America, it forms part of the border between Canada and the US, specifically between Quebec and New York/Vermont. I remember driving along the Montana-Wyoming border and realizing I was right on it! It also zips through states like Oregon, Idaho, and even parts of the Midwest like Minnesota, Wisconsin, and Michigan.

Hop across the Atlantic, and you’ll find it meandering through Europe, including France and Italy. Then it’s on to Asia, with a pit stop in Mongolia. And, of course, it crosses a whole bunch of water: the Pacific and Atlantic Oceans, the Black Sea, the Caspian Sea, and even the Sea of Japan. Talk about a scenic route!

Daylight’s Dance

Here’s another fun fact: the 45th parallel plays a role in how much daylight you get. In the peak of summer (the summer solstice), you’ll soak up about 15 hours and 37 minutes of sunshine. But come winter (the winter solstice), that shrinks to a mere 8 hours and 46 minutes. It’s a pretty dramatic difference, and something folks living along that latitude definitely notice throughout the year.