This is the least exciting subject in temporary structures and the only one that ever makes the news.

A rating is a configuration, not a product

The same marquee has different ratings staked into firm ground, ballasted on tarmac, and ballasted with sidewalls fitted. Quoting one number for ‘the tent’ is meaningless.

Ask for the rating in the configuration you will actually use, on the surface you will actually stand it on. If the answer changes when you mention sidewalls, that is a supplier who is thinking about it correctly.

Walls turn a structure into a sail

An open-sided frame lets wind pass through. Fit solid sidewalls and the same frame becomes a surface for the wind to push against, and the loads go up sharply.

This is why the first action in rising wind is always to drop the walls, not to add more ballast. It is quick, it is reversible, and it buys a large margin.

Set a threshold before the day

Decide the de-rig wind speed in advance, write it in the event plan, and name the person who calls it. Thresholds decided in the moment are decided badly, because by then there is a schedule and an audience pushing the other way.

Get a handheld anemometer. They cost very little and they replace an argument about whether it feels windy with a number.

Overnight is the risk window

Most structural failures happen when nobody is on site. If a tent stands overnight, fit storm straps over the roof, check the ballast before you leave, and have somebody who can get there.

If the forecast is genuinely bad, the correct answer is to strike it in the evening and rebuild in the morning. That is a cost; it is a much smaller one than the alternative.