**Official observations from London Heathrow and other Met Office stations recorded a daily maximum of 22°C on October 4, 2026, under partly cloudy skies with light westerly winds and no precipitation.** This value exceeds the 1991–2020 climatological average high of 17.5°C yet falls within documented warm anomalies for the date, including the all-time record of 22.9°C set in 1965. Numerical weather models converged on this peak during the afternoon, with surface analyses confirming the reading before evening cooling. The market-implied odds reflect this strong observational consensus backed by real capital. A realistic challenge would require post-event data revision from the primary reporting station or an undetected microclimate effect elevating another site above 22°C, though such adjustments are rare once multiple stations align.