Trader consensus on Polymarket has locked in 8°C as the lowest temperature in London on May 6, 2026, at 100% implied probability, driven by the latest Met Office forecast for Greater London confirming an overnight minimum of 8°C amid partly cloudy skies and light northerly winds around 6–8 mph. This aligns with hourly projections showing temperatures bottoming out near 9°C early evening before stabilizing at 8°C, bolstered by the urban heat island effect and sufficient cloud cover to curb radiative cooling—conditions validated by current observations of 11–12°C in the evening. Model consensus from UKV and ECMWF supports this, with morning lows already exceeding 7°C. Realistic challenges include unexpected clearing leading to a brief dip toward 7°C under ideal inversion conditions, though persistent breeze and humidity above 70% render it highly unlikely; final Heathrow Airport data will resolve the market by midnight.