**Forecast consensus from multiple models points to an overnight low near 15°C for Buenos Aires on September 28, driven by persistent easterly to southeasterly flow off the Atlantic and widespread cloud cover that limits radiative cooling.** This springtime pattern features mild advection with dew points in the 13–15°C range and light-to-moderate winds (5–10 m/s), which mix the boundary layer and prevent sharp temperature drops. Historical September climatology shows average lows around 11–13°C, but current conditions reflect a warmer-than-normal marine influence. The closely matched market-implied odds on 11°C or below versus 21°C or higher reflect residual model spread in cloud timing and any late southerly shift that could either enhance cooling or maintain mild conditions through the night. Updated runs from agencies such as the National Meteorological Service will clarify whether the minimum settles in the 14–16°C band or deviates.