Recent Met Office forecasts indicate a daytime maximum of 26°C for London on August 5, underpinning the near-even split between 25°C and 26°C outcomes in trader sentiment. Ensemble model runs show modest variability driven by the precise strength of high pressure, Atlantic frontal timing, and boundary-layer mixing, which can shift peak readings by 1–2°C. Urban heat-island effects at official stations and light wind regimes further influence whether the thermometer registers the upper or lower end of the narrow range, while historical August climatology places typical London highs near 22–23°C. Updated model guidance and any late-day convective development over the next 48 hours remain the key variables for resolution.