Persistent southwesterly flow and widespread cloud cover associated with an unsettled Atlantic low-pressure system are capping insolation and advecting cooler maritime air across southeast England, keeping forecast maximums tightly clustered around 20–22 °C for 29 August. Official guidance from the Met Office and ensemble output place the daytime peak near 22 °C under mostly overcast skies with periods of rain, while some guidance shows slightly lower values near 18–20 °C if heavier showers persist through the afternoon. The narrow spread in market-implied probabilities (21 °C at 27 %, 22 °C at 25 %, 20 °C at 18.5 %) reflects modest ensemble divergence in cloud timing and boundary-layer mixing rather than any large-scale regime shift. Updated model runs and surface observations over the next 48 hours will determine whether brief breaks allow temperatures to reach the upper end of the distribution.