Recent forecasts from the Met Office and BBC indicate a mild overnight period for London on August 19, with minimum temperatures likely settling near 13–15°C under variable high pressure and light westerly winds. The tight clustering of market-implied odds around 16°C and 17°C reflects genuine model uncertainty in nocturnal radiative cooling rates, influenced by potential increases in low-level cloud or humidity that could limit temperature drops. Clearer skies would favor stronger surface heat loss and values closer to 14–15°C, while any increase in wind or cloud cover would moderate the minimum upward. Updated ensemble runs and 48-hour outlooks from official agencies remain the key near-term catalysts.