**Recent Met Office forecasts and station observations indicate a minimum temperature near 14°C for London on September 20, 2026, driving the overwhelming market consensus at that level.** Clear skies under high pressure have allowed typical nocturnal radiative cooling, with daytime highs reaching 21–23°C and overnight lows projected at 11–13°C at Heathrow and central sites, aligning closely with the 1991–2020 climatological average low of 11.2°C. Model consensus supports this range without significant divergence, and real-time observations through evening show temperatures holding above 13°C before further gradual decline. The market-implied 99.8% probability on 14°C reflects traders’ assessment of these stable conditions and the precise resolution criteria tied to official daily minimums. A shift could occur only if late-night wind increases or unexpected cloud cover reduces cooling, or if the recording station reports a value outside the narrow 13–15°C band.