Persistent cloud cover, widespread rainfall, and southwesterly winds are suppressing daytime solar heating across London on August 29, keeping maximum temperatures in the narrow 19–21 °C range according to Met Office and ensemble forecasts. These conditions reflect an unsettled late-summer pattern that limits boundary-layer warming despite near-normal seasonal insolation. Market-implied odds place 21 °C at 44.5 % and 20 °C at 36 %, consistent with model consensus on peak values before heavier afternoon rain arrives, while lower probabilities for 19 °C or 22 °C reflect remaining uncertainty in exact timing and intensity of showers. Official observations through the morning show readings near 18–19 °C, supporting trader focus on whether brief clear spells allow a late-day spike.