**Forecast models indicate the overnight minimum in London on September 1, 2026, is most likely to settle near 12–14 °C, consistent with the market’s leading outcomes of 13 °C (42 %), 14 °C (21.5 %), and 12 °C (18 %).** Short-range guidance from the Met Office and global ensembles shows a dry, partly cloudy night with light westerly winds under building high pressure following scattered showers on August 31. This setup favors moderate radiative cooling after daytime highs near 22 °C, producing lows typically 12–16 °C. Historical climatology for September 1 at London Heathrow gives an average minimum of 12.8 °C, providing a baseline against which current model runs sit close to or slightly above normal. Uncertainty in the exact minimum arises from small variations in cloud cover, wind speed, and the precise timing of any residual moisture; ensemble spreads commonly place the 10th–90th percentile range across 11–15 °C. Traders are therefore concentrating probability on the central 12–14 °C band while assigning lower weight to warmer outcomes above 15 °C or colder readings below 11 °C. Fresh model updates expected in the next 24–48 hours will likely narrow this range ahead of resolution.