Official Met Office observations for London on May 20 recorded a daytime maximum temperature of 20°C, aligning precisely with the market’s near-certain consensus. This outcome reflects stable high-pressure conditions that limited cloud cover and produced typical May insolation levels, yielding a modest diurnal temperature range consistent with long-term climatological averages for the region. While ensemble forecast models initially showed minor spread around the central value, the final verified reading from the designated urban station resolved any residual uncertainty. Traders can expect limited movement unless post-event quality-control adjustments alter the official maximum, an uncommon occurrence once preliminary data are released.