Forecast models for Buenos Aires on August 21 indicate overnight radiative cooling under partly cloudy skies and light southerly winds, with minimum temperatures most likely falling between 4°C and 7°C by early morning. This produces the tightly clustered market-implied odds around 2–5°C, as ensemble runs from agencies like the Servicio Meteorológico Nacional and international centers show modest spread driven by cloud-cover timing, dew-point depression, and urban heat-island effects that can shift the precise hourly low by 1–2°C. Clearer conditions favor the lower end of that range through enhanced longwave radiation loss, while any increase in low-level moisture or wind would limit the drop; extremes below 1°C or above 8°C remain improbable given the current stable winter air mass and climatological baselines near 6–8°C.