Andy Devaney
In the ever-evolving world of rugby, 2025 has brought more than just fresh tactics and new talent—it’s brought a hard-nosed, no-nonsense approach to playing in the kind of heat that makes a steak sizzle before it hits the grill.
World Rugby, not one to shy away from a scrummage with climate realities, has rolled out updated heat and air quality guidelines that aim to keep players safe when the mercury soars and the turf starts to steam.
This isn’t some vague nod to player welfare. It’s a scientifically rigorous revamp, thanks to Dr Grant Lynch and Dr Olly Jay of the University of Sydney.
They’ve cooked up a new Heat Stress Index—an elegant bit of sport science that goes beyond just reading a thermometer. Instead, it mixes air temperature, humidity, wind speed, and ground radiation into a single index that runs from 0 to 250. Depending on the score, decisions are made on the fly to cool things down before players keel over.
Here’s how it breaks down, rugby-style:
- Low (0–99): It’s business as usual—hydrate, huddle, hammer the line.
- Moderate (100–149): Less kit, more water. Not quite a spa day, but close.
- High (150–199): Cue the three-minute cooling breaks in each half, along with icy towels and glances toward the sun.
- Very High (200–249): Half-time gets a five-minute extension to 20 minutes. Coaches might even get a word in.
- Extreme (250+): Pack up the ball and wait it out—games may be postponed or suspended.
And lest anyone try to muscle through a match when the ground’s radiating like a barbecue lid, World Rugby has installed EMU devices to take the guesswork out of the equation. These handy little gadgets constantly assess the playing conditions with the precision of a neurosurgeon.
Should a game hit the “Extreme” threshold and get paused, there’s a strict resumption protocol. The Heat Stress Index must dip below 230 and stay there for 45 minutes, forecasts must promise it won’t spike again for a couple of hours, and—most critically—the Match-Day Doctor must give the green light. This isn’t just box-ticking—it’s serious duty-of-care stuff, delivered with the sort of clarity that would make a referee proud.
“Ultimately, we want players to perform at their best without risking their health,” said Dr Grant Lynch. “These guidelines offer a robust, evidence-based framework to ensure safety without compromising the integrity of the sport.”
With global temperatures rising and summer tournaments heating up in more ways than one, these guidelines could very well set the standard not just for rugby, but for all outdoor sports looking to tackle climate realities head-on.
As the game changes, so too does the environment it’s played in. World Rugby’s new measures are a timely, sensible response—forward-thinking without forgetting the roots of the sport. And in a game that thrives on resilience and grit, this might just be the smartest play yet.
You can find the full heat and air quality guidelines, as well as the official Heat Stress Index calculator, on the World Rugby website.
