Heat thresholds only work if someone is obliged to obey them

Wet bulb readings trigger cooling breaks in most competitions, and the reading is usually taken by an official with reasons to prefer a low one.

A number on a meter decides whether players get to stop. Which meter, held where, and by whom, is where the rule quietly falls apart.

Most competitions now use a wet bulb globe temperature threshold to trigger mandatory cooling breaks, and that is genuine progress; a combined measure of heat, humidity and radiant load is far better than air temperature alone. The regulation typically says a break shall be taken above a stated value. Then it stops talking, and everything that determines whether the rule works is in the silence.

Where does the meter sit? A device in the shade of the officials' tent will read lower than one on the surface where the game is played, and artificial turf on a still afternoon can be a different climate altogether from the grass twenty metres away. Who reads it? Frequently the match commissioner, who is also the person whose event overruns if a break is called. Is the reading published? Almost never at amateur level, which means a decision with real consequences is made privately with no record.

None of that requires bad faith to go wrong. It just requires ordinary human reluctance to be the one who delays a fixture, and that reluctance sits on the side of not stopping every single time.

I would make three changes and none of them are expensive. Fix the measurement point in the rules, on the field of play, at a stated height. Require the reading to be logged and given to both teams before the match, and again at halftime. And take the decision away from the person running the event by making the break automatic above the threshold, no discretion, the way a lightning protocol works.

Officials will tell you the threshold is followed. Ask them who checked it at half past two, and the answer gets vaguer. The lightning comparison is the one that convinces me. Nobody argues about lightning. It is automatic, everyone leaves, and no official is asked to weigh the schedule against the risk. Heat kills more athletes than lightning does, and we treat it as a matter for judgement, mostly because heat does not make a noise.