Recent Met Office guidance projecting a 30°C daytime maximum in London on August 12 has centered trader focus on the 30°C and 31°C outcomes, which together hold nearly two-thirds of the market-implied probability amid tight spreads. Persistent high pressure and warm air advection from the south have sustained above-average conditions through early August, pushing readings several degrees above the long-term seasonal norm of roughly 21–22°C. Minor differences among ensemble models regarding peak solar heating, boundary-layer mixing, and any late-day cloud development create the narrow uncertainty between 29°C and 32°C. Updated short-range runs and observational data in the next 48 hours will likely refine these probabilities ahead of resolution.