Recent Met Office guidance and ensemble forecasts show a cold front crossing southern England overnight on October 15, shifting winds to the northwest and advecting cooler maritime air that caps daytime heating. This follows Thursday’s 21°C peak under southerly flow, with October 16 expected to reach only 15–16°C amid morning showers and gradual afternoon clearing. Model spread in shower timing and boundary-layer mixing creates the narrow gap between 16°C and 17°C outcomes that dominate market pricing, while historical October maxima near 15.7°C provide context for the current trader consensus. Updated NWP runs and surface observations through the morning will refine the precise peak.