What the Numbers at the End of the Runway Really Mean
The numbers at the end of the runway are not only needed so that pilots can see where they should land. They actually mean something important: the degree of the runway from magnetic north. This video from Atlas Obscura explains.
The video is only about a minute long, so it’s worth watching even though the cat is out of the bag here – each runway number represents a different degree, labeled 1 to 36 – from magnetic north, rounded to the smallest two-digit number. So, for example, Runway 12 is 120 degrees from Magnetic North and Runway 36 is 360 degrees from Magnetic North, which means you are pointing directly north.
That being said, magnetic north is known to shift and move long distances over time, which then makes all of these numbers completely wrong when it does. If necessary, this means changing the runway number, which also means repainting the number on the runway. This is not the most practical information, but it can definitely be used the next time you take off and arrive for a landing or take off from an airport to get some idea of your relationship with the planet.
Runway numbers | Everything is decrypted | Atlas Obscura (YouTube)