Forecast models and real-time observations from agencies including Spain’s AEMET point to a maximum of 36 °C in Madrid on September 15, 2026, under clear skies, light winds, and negligible precipitation risk, producing the market’s near-certain consensus. This value sits well above the 1991–2020 average high of roughly 27 °C for the date and exceeds the all-time September 15 record of 34.3 °C set in 1987. Traders have aligned with the latest high-resolution model runs showing minimal spread and no signs of cooling advection or increased cloud cover through the afternoon peak. A modest downward revision in the final AEMET or ECMWF update, localized measurement differences at official stations, or an unanticipated sea-breeze effect could still shift the verified maximum into the 34–35 °C range before resolution.