Recent forecast models from agencies like the Met Office and ECMWF indicate London’s overnight minimum on August 21 will likely settle near 12–14 °C under mild, changeable summer conditions with light winds and variable cloud cover. Trader consensus clusters on 13 °C and 14 °C because these align with ensemble guidance showing modest radiative cooling under partly cloudy skies, tempered by urban heat retention and possible weak Atlantic flow. Clearer or calmer nights could push readings toward 12 °C, while increased cloud or stronger mixing favors 14–15 °C; longer-range signals of near-average August temperatures and limited high-pressure dominance keep probabilities balanced rather than skewed lower. Updated model runs over the next 48 hours will refine the exact threshold.