Recent short-range model runs, including Met Office guidance and GFS output, point to a 22°C high in London on September 1 under building high pressure, light westerly winds, and limited cloud cover that favors modest daytime radiative warming. Seasonal norms for early September hover near 20–22°C, so the forecast aligns closely with climatology while remaining sensitive to small shifts in timing of any residual Atlantic moisture or wind direction. Ensemble spread in operational models supports the tight clustering around 22–23°C, with lower odds for 24°C or above reflecting limited potential for stronger insolation or warmer advection. Traders appear to price in modest upside uncertainty from local urban heat effects or minor forecast revisions expected in the next 24–48 hours.