Recent Met Office and BBC forecasts for London on August 20 highlight a post-heatwave cooldown under northerly flow, with daytime maxima expected near 22–23°C amid light showers and increased cloud cover. Ensemble guidance shows modest spread due to variable shower timing and coverage, which can suppress peak readings by 1–2°C through reduced insolation while clearer intervals allow brief climbs toward 24°C. This aligns with seasonal norms around 22°C after the mid-August spike to 38.1°C, as models converge on gentle westerlies and limited instability rather than strong high pressure. Traders assign the highest implied probability to 23°C because official point forecasts cluster there, with adjacent bins reflecting uncertainty in convective details and exact steering patterns ahead of final model runs.