Mid-Week Mini: The Eiffel Tower’s Growth Spurt

In this week’s Mid-Week Mini Episode, we talk about how the Eiffel Tower suffers from shrinkage when it’s cold!

You’ve probably seen the Eiffel Tower a thousand times. In movies. In photos. On someone’s Instagram captioned “no filter” even though there’s definitely a filter. But here’s the part people don’t usually tell you – the Eiffel Tower is taller in the summer than it is in the winter. And not by a rounding error. By up to six inches.

That means if you visited Paris in January and again in August, you’d be looking at two slightly different towers. Same iron. Same rivets. Same tourists. Different height.

The reason is something incredibly boring-sounding that turns out to be extremely cool: thermal expansion. When materials heat up, the atoms inside them start vibrating more. That vibration makes them spread out just a little. Multiply “just a little” by 18,000 individual iron pieces, all riveted together, and suddenly your tower is growing like it’s trying to impress someone.

The Eiffel Tower is made almost entirely of wrought iron, which is especially responsive to temperature changes. On a hot Paris summer day – especially during a heat wave – the metal expands enough that the tower can grow about 15 centimeters, or roughly 6 inches. In winter, it shrinks back down again. No damage. No bending. Just a seasonal growth spurt.

What’s wild is that this wasn’t an accident or a design flaw. The tower was engineered with this exact behavior in mind. The base of the structure is anchored in such a way that it can subtly shift and accommodate expansion without cracking or stressing the iron. Even the slight lean the tower gets in the sun – yes, it can lean a bit – was anticipated. As the sun heats one side more than the other, the tower can tilt by a few inches before evening temperatures even things back out.

And it’s not just height. The iron staircases inside the tower can expand too, which is why some maintenance measurements are always taken at standardized temperatures. Engineers learned early on that if you measure the tower on a hot afternoon and compare it to a cold morning, you might think something’s gone very wrong. When really, the tower’s just… warm.

So if you’ve ever taken a summer photo at the Eiffel Tower and thought, “Wow, this feels bigger than I imagined,” you weren’t wrong. It literally was.

The Eiffel Tower grows in the heat, shrinks in the cold, and quietly reminds us that even the most iconic landmarks in the world are still obeying the same basic rules of physics as everything else.

The internet says it’s true.