Recent Met Office guidance and ensemble models indicate London's overnight minimum on August 18 will likely settle near 16–18 °C under a moderating post-heatwave pattern. After daytime highs reached 34 °C on August 14, a shift toward increased cloud cover, lighter winds, and possible showers has reduced radiative cooling overnight, keeping temperatures above the seasonal average low of roughly 14 °C. Current forecasts show daytime maxima near 26 °C on the 18th with minimums of 16 °C, reflecting consensus across guidance that favors 17–18 °C as the most probable overnight readings. These outcomes align with the strongest market-implied probabilities because ensemble spreads remain narrow and no major model divergence has emerged in the past 48 hours. Upcoming updates from the Met Office and ECMWF runs will be the key near-term catalysts.