These events are fixed to the calendar — the same days, the same places, most years. Measuring their conditions against the historical record for that exact place and date shows what has changed beneath them, stage by stage and day by day, rather than relying on a single seasonal average.
Methodology inspired by Cvijanovic, I., Begg, J.D., Mistry, M.N., Petrova, D., Brimicombe, C., Sultan, B. (2026), "The future of European outdoor summer sports through the lens of 50 years of the Tour de France," Scientific Reports (open access). Full citation on the methodology page.