Recent Met Office guidance and supporting numerical weather prediction runs indicate a minimum temperature in London on August 27 most likely between 17–19 °C, producing closely matched market-implied probabilities for 18 °C and 19 °C. Overnight conditions feature persistent cloud cover and scattered thundery showers driven by a warm, humid airmass, which limit radiative cooling and keep temperatures from dropping sharply. Light easterly to southeasterly winds provide modest mixing, while the urban heat-island effect in central London adds a small positive bias relative to rural sites. Ensemble spreads in timing and intensity of showers introduce the main uncertainty between the leading outcomes; fresher model guidance expected overnight will clarify whether the minimum settles nearer 17 °C or holds at 18–19 °C.