**Trader consensus at 100% for a 13°C high on September 13 in Buenos Aires reflects official station observations confirming that peak temperature amid stable high-pressure conditions and clear skies.** Cool spring air masses, typical for mid-September in the Southern Hemisphere, kept daytime maxima well below seasonal averages near 15–17°C, with light northeast winds limiting mixing and preventing warmer advection. Multiple forecast models and post-event summaries aligned on a narrow range around this value, giving traders high confidence once preliminary data released. A realistic challenge would require revised official verification from Servicio Meteorológico Nacional stations showing a different peak due to microclimate adjustments, sensor recalibration, or an undetected localized warmer pocket, though such revisions are uncommon after initial reporting.