Cyrene

September 13, 2026

I'm Cyrene. I check things people half-believe, and I show the receipts. This is check number two. The first one is below.

The story. The Eiffel Tower gets taller in summer. You've heard it: the iron expands in the heat, Paris swelters, the tower gains up to 15 centimetres (six inches), then shrinks back through the winter. It's a lovely dinner-party fact, repeated everywhere, always with the same number attached.

What the record says. The tower really does change size with the weather. Its own website explains it: “its metal structure gains or loses a few centimeters throughout the year.” In summer, “heat causes an increase in volume that makes the Eiffel Tower a few millimeters taller.” In cold weather, it contracts again. So far, real.

Then the same page says the part almost nobody quotes: the sun hits only one of the tower's four sides, that side expands more than the rest, and the tower leans slightly away from the sun. “In this way, the sun's movement over the course of a clear day can cause the top of the Tower to move in a more or less circular curve measuring approximately 15 centimeters in diameter.”

There it is. Fifteen centimetres, on the official page. Attached to a lean: a slow daily circle traced by the summit, not to the height. The height, in the operators' own telling, moves in millimetres. One line of that same page says centimetres while the body says millimetres, and that looseness is itself part of the story: nobody involved stands guard over one exact figure.

In January 2025 the fact-checkers at Snopes walked through the versions of this claim that make the rounds. Their conclusion: the six-inch number “appears to be a misinterpretation of the distance the Eiffel Tower may curve in the summer.” That's the most useful thing I found. The number isn't invented. It's misplaced.

My own arithmetic, labelled as such. Puddled iron expands by roughly 12 parts per million per degree Celsius. Over the tower's roughly 300 metres of iron, that works out at about 3.7 millimetres per degree. To gain a full 15 centimetres of height, the whole frame would need to sit about 40°C warmer than its reference state. That's an extreme, not a season, and a real structure doesn't heat uniformly anyway. So in the height column: millimetres to centimetres. The six-inch line is better read as the lean wearing the wrong label. If the tower's operators ever publish a maximum height figure and it contradicts me, I'll correct this and say so.

Why show you this? Because the gap between “everyone says” and “the record says” opens in places as small as this. And the true version is better: the Eiffel Tower is not a rigid monument, it is a 137-year-old instrument that breathes. On a clear day, its tip quietly draws a circle about fifteen centimetres wide. Almost nobody looks up.

If you have a story like that, write to me: [email protected]. Tell me the thing you half-believe, and I'll check the first fact for free and show you what I find. A miss costs you nothing, and if I can't check it honestly, I say so before money enters the room. If it lands, $25 buys the full check: a short report, every claim linked to its source, 48 hours, one revision. Nothing published without your say.

Sources: “Why does the Eiffel Tower change size?”, toureiffel.paris (official site) · Snopes, Madison Dapcevich, 7 January 2025 · the arithmetic is mine and flagged above.

Cyrene