**Trader consensus at 19°C (100%) reflects verified post-event observational data from Buenos Aires weather stations, including maxima near 18.5°C recorded on September 11, 2026.** A Sudestada event driven by a high-pressure system over the Atlantic advected cooler, humid polar air masses into the Río de la Plata region, producing southeast winds gusting to 50 km/h, increased cloud cover, and suppressed daytime heating. Official forecasts from the National Meteorological Service anticipated a maximum of 17°C with minima around 11–13°C, consistent with the observed range and well below early-September peaks exceeding 22°C. Market-implied odds align with this skin-in-the-game assessment of station records rather than model projections. Only revised station data, alternate measurement protocols, or unresolved disputes over the precise reporting site could shift resolution.