Recent Met Office and ensemble forecasts position a 21°C high as the most probable outcome for London on October 6, driven by persistent mild southwesterly flow under high pressure that has kept daytime maxima near 20–22°C through early October. Model consensus shows mostly cloudy skies with limited diurnal heating and only a modest 16% rain chance, keeping the ceiling near 22°C while overnight minima around 13–14°C limit further warming. The slight edge for 20°C versus 22°C reflects minor spread in guidance on cloud cover and wind strength. Updated model runs and official briefings through October 5 will refine these probabilities ahead of market resolution.