Latest Met Office and ensemble forecasts point to a maximum of 22–23 °C in London on 27 September, driven by southerly flow advecting milder maritime air beneath weakening high pressure. Partial cloud cover and scattered showers expected during peak heating hours will limit insolation and cap the diurnal rise, while light winds reduce mixing. Model spreads arise mainly from differences in timing of frontal cloud and moisture advection, producing the tight clustering of market-implied odds around 22–24 °C. Updated runs from the National Meteorological Service and global models later today will refine whether the peak reaches the upper or lower end of that narrow range.