Recent Met Office and ECMWF model runs indicate a mild southwesterly flow over southern England on September 14, supporting a maximum temperature near 24–25 °C under mostly cloudy skies with limited daytime heating from reduced insolation. Ensemble spreads reflect minor uncertainties in afternoon cloud breaks and boundary-layer mixing that could nudge readings a degree either side of the central forecast, consistent with the closely matched 36.5 % and 29.5 % market-implied probabilities for 24 °C and 25 °C. These outcomes sit within normal September variability for London, where historical averages hover around 19–20 °C but occasional warm advection episodes push peaks into the mid-20s when winds remain light and humidity moderate. Updated guidance expected from the Met Office and new model cycles will clarify whether stronger mixing or increased cloudiness shifts the most likely peak.