Why 27.4 °C? The story behind the number
How one decimal place ended a decade of argument.
Before 1968 there was no standard water temperature at all, and finals between 1951 and 1967 were held in water from 19.8 °C to 25.9 °C. The Great Chlorine Schism of 1968 split the sport into Indoor and Outdoor championships, and three years later Congress fixed the Indoor temperature at 27.4 °C ± 0.2 °C.
The figure sits inside the 25–28 °C band used for competitive swimming. Water conducts heat roughly 20 to 25 times better than air, so a few tenths of a degree matter over a long championship. The Archive shows that each 1 °C rise in water temperature is associated with about 3.5% fewer tags per chukka.
The full science is on the Indoor vs Outdoor page.
FIMP Media · Photo: z pm / Unsplash
