**A heatwave driven by high pressure and southerly flow is keeping overnight lows elevated across southeast England, pushing the market-implied probability for London’s July 9 minimum toward the 18–20 °C range.** Current model consensus from the Met Office and ECMWF shows daytime maxima of 27–34 °C mid-week, with “tropical nights” where urban heat-island effects and light winds limit radiative cooling, holding minima near or above 18 °C. This aligns with the tight clustering of leading outcomes (18 °C or below at 47.5 %, 20 °C at 44.5 %). Forecasters note that exact nocturnal temperatures remain sensitive to small changes in cloud cover, wind speed, and boundary-layer moisture; later model runs could shift the minimum by 1–2 °C either way. Historical July averages (around 14–15 °C) highlight the anomaly, but traders are weighting the short-term dynamical forecast more heavily as resolution nears.