London's August 2026 precipitation totaled just 12 mm according to station data, far below the 52 mm long-term average and well under the 30 mm threshold. Persistent high-pressure systems, above-average temperatures reaching 37.7 °C, and minimal frontal activity produced widespread dry conditions across southeastern England, where regional totals reached only 35.2 mm or 56 % of normal. Official Met Office summaries confirm eight of nine UK regions recorded below-average rainfall, with drought declarations persisting through late August. Traders' 97.5 % implied probability on the <30 mm outcome directly tracks these verified measurements. Only substantial late-month revisions to official totals or reclassification of trace events could alter resolution.