Official Met Office guidance for London on September 25 points to a minimum of 12°C under clear to partly cloudy skies with light northerly winds, supporting strong market consensus around that threshold. Recent high-pressure dominance and stable conditions have limited cloud cover and moisture, allowing typical radiational cooling overnight without significant advection of warmer air. Historical September minima in the region often fall near 11–13°C under similar setups, providing climatological context. Shifts in forecast models showing increased overnight cloud or stronger winds could prevent temperatures from reaching exactly 12°C, while an unexpected cold surge remains unlikely given current steering patterns and ensemble agreement.