The Tour de France has always paired with intense midday sun, stretching back well before air conditioning glitches in team buses became headline news. Turning to Geoffrey Nicholson's classic book The Great Bike Race from fifty years ago reveals accounts of a sweltering start in the Vendée followed by scorching days across central France and Normandy.

"The heatwave," Nicholson observed, "is emerging as a real problem." He recalls Raymond Poulidor as a veteran of such trials who restricted himself to two litres of fluid per stage, reflecting the peloton view that extra water brought on tiredness. Modern riders would find that notion surprising as they drain bottle after bottle.

Nicholson evokes earlier forgotten heatwaves, including 1951 when Fausto Coppi lost thirty three minutes to the Languedoc sun on the way to Montpellier, and the punishing 1957 edition in Normandy that saw sixty six of one hundred twenty starters abandon.

Even though he wrote about the dry summer of 1976, those temperatures look mild beside the furnace like conditions of recent years, with twenty five degrees in the Vendée and twenty nine on the road to Caen.

Today's competitors, who pack ice filled stockings around their necks and supply urine samples to monitor fluid loss, would welcome those milder figures. One likened the latest spell to "riding into a hair dryer."

Old rules on racing in heat now appear archaic. During the nineteen sixties, when Tom Simpson collapsed fatally on Mont Ventoux, riders were limited to four bidons daily. After his death the policy changed, yet before that change riders stopped at bars or springs and sometimes picked up infections.

Without modern knowledge of heat stress, some ate salted cod while training to build tolerance; magazines from the nineteen eighties even showed riders tucking cabbage leaves inside their caps for neck protection.

As temperatures climbed, teams adopted new tactics. In 2004 Great Britain used ice bath chairs so riders could cool their wrists and lower core heat. By 2010 Team Sky worked with Gatorade on individual mineral tests and relied on ice baths plus ice stockings.

One squad may now consume eighty to one hundred kilograms of ice daily, plus custom ice treats adjusted for salt content.

Adaptation has limits, however, and rising global temperatures will force organisers to consider major schedule changes, even in a sport backed by oil interests. Carbon awareness has already increased, with spectators urged to cycle and electric vehicles replacing some diesel units.

Finishes without crowds, as seen at Les Angles, will not appeal to host towns seeking tourism revenue.

Amateur events across France have been altered or cancelled amid the late June heat, while Alpine mudslides on the Col de Sarenne echo problems from 2019 and prompt extra vigilance.

The fixed July slot and afternoon television finishes may soon shift. The era of cabbage leaves and salted cod has ended; fiercer conditions lie ahead.