Official Met Office observations from London Heathrow Airport—the standard reference station for such markets—recorded a maximum temperature of 11°C on March 28, solidifying trader consensus at virtually 100% implied probability for this outcome amid cool northerly winds, extensive cloud cover, and limited solar heating. This aligns precisely with pre-event forecast ensembles from the Met Office and ECMWF models, which converged on a 10–11°C range due to a blocking high-pressure system steering chilly air masses southward. Late March climatology supports this, with historical Heathrow averages near 11°C, though occasional warm anomalies occur. Realistic challenges are negligible post-resolution, barring rare data revisions from quality-controlled measurements.