Southeast winds advecting a cooler maritime air mass drove the primary uncertainty in Buenos Aires minimum temperatures for September 11, with National Meteorological Service forecasts centering on an 11°C low amid mostly cloudy skies and gusts to 50 km/h. Actual station data recorded a minimum of 12.7°C, above the 9–8°C range favored by traders at 51% and 46% implied probability. Model spread in boundary-layer mixing and local urban heat retention created the tight clustering around these thresholds, as modest forecast revisions of 1–2°C can shift resolution between adjacent bins. Historical September averages near 11–12°C provided limited guidance given the recent cold outbreak earlier in the month. Updated observational verification from official networks is expected to finalize market settlement shortly.