Recent Met Office guidance for London on August 4 projects a daytime high near 28°C followed by an overnight low of 19°C under mostly clear conditions, anchoring trader focus on the 19–21°C outcomes. Ensemble model runs show modest spread in boundary-layer mixing and cloud cover overnight, with lighter winds favoring slightly warmer minima around 20–21°C in some solutions. This aligns with the broader warm anomaly persisting across southern England, where summer temperatures have run 1.8–2.4°C above the 1991–2020 baseline. Resolution hinges on the official 24-hour minimum recorded at representative stations, and fresh model guidance expected within 48 hours could shift implied probabilities before the period closes.