**Official forecasts from the UK Met Office and supporting models indicate a daytime maximum of 21°C for London on October 15, 2026, under mostly cloudy skies with sunny intervals and only a low (10–30%) chance of light rain.** This aligns with current morning observations showing temperatures climbing from the mid-teens toward an afternoon peak near 21°C, driven by mild southerly or southwesterly flow and limited cloud cover that allows sufficient solar heating for October. Historical climatology for mid-October places typical highs around 15–17°C, making today’s conditions anomalously warm due to the persistent high-pressure influence and above-average air mass temperatures. Market-implied odds favor 21°C (49.5%) over 22°C (37.5%) because ensemble guidance and official guidance show little support for exceeding 21°C, though minor upward revisions remain possible if localized heating or measurement timing pushes the peak slightly higher. No major forecast shifts have occurred in the past 24 hours, and resolution will hinge on the official recorded maximum from standard London stations.