Forecast models from Argentina’s Servicio Meteorológico Nacional and international ensembles indicate a moderating northerly flow over Buenos Aires on September 23, supporting maximum temperatures near 17–19 °C under mostly cloudy skies and light winds. Northerly advection of warmer maritime air, combined with limited insolation from persistent cloud cover, caps the diurnal rise and reduces the chance of reaching 20 °C or higher. El Niño conditions, now strengthening in the equatorial Pacific, favor above-average spring warmth regionally but exert only indirect influence on this short-term event through altered steering patterns. Traders assign roughly equal implied probabilities (19–20.5 %) to 18–21 °C outcomes because small shifts in model runs—such as wind direction or timing of frontal passage—can easily move the daily maximum across those thresholds, while extremes below 16 °C or above 22 °C remain low-probability given current guidance. Updated model cycles and official observations will provide the next key signals before resolution.