Recent forecasts from multiple models indicate a likely overnight low near 13–14°C for London on June 13, driven by clearing skies and light winds under a building high-pressure ridge following the cool, unsettled pattern after May’s heat. Clear conditions promote radiative cooling after sunset, while modest northerly flow limits warm-air advection; small differences in cloud timing or boundary-layer mixing explain the tight clustering of market-implied odds between 13°C and 15°C. Ensemble spreads remain modest this close to the event, but any increase in low-level moisture or wind speed could raise the minimum by 1–2°C, whereas prolonged clear, calm nights favor the lower end of the distribution. Updated Met Office and ECMWF runs expected within 24 hours will likely narrow the range further.