**Forecast uncertainty in the overnight minimum temperature is driving the tight clustering of market-implied probabilities around 6–12°C.** Official and ensemble model guidance for Buenos Aires on August 30, 2026 (late winter in the Southern Hemisphere) shows a daytime high near 16–19°C under mostly sunny to partly cloudy skies with light easterly to northeasterly flow, followed by an overnight low that varies across sources between roughly 9–13°C. Key differentiating factors include the strength of nocturnal radiative cooling under variable cloud cover, boundary-layer moisture and dew-point depression, and subtle differences in steering winds that influence how quickly temperatures fall after sunset. Some model runs (e.g., certain global ensembles) favor a clearer, calmer night supporting a dip toward 9–11°C, while others keep more cloud or slightly stronger mixing that holds the minimum closer to 12–13°C. Historical August climatology places the typical daily minimum near 7–8°C, so current conditions are running mildly above average, yet the exact departure remains sensitive to small changes in the 00–06 UTC window when the daily low is usually observed. Because the resolution hinges on a single verified station reading (most likely the official Servicio Meteorológico Nacional site), traders are pricing in both the consensus central tendency near 10–12°C and the realistic tail risk of a sharper drop or a warmer floor, resulting in the observed near-even odds across the 6–12°C band. New model runs or updated observational data overnight will be the primary catalysts for any sharp repricing.