Trader consensus on Polymarket favors a 14°C high in London on April 12 at 45% implied probability, with 15°C close behind at 34.5%, reflecting the latest Met Office forecast of peak temperatures around 14-15°C amid light showers and gusty westerly winds up to 30mph. This positioning stems from a sharp cooldown after mid-week record warmth above 26°C, driven by continental high pressure giving way to an Atlantic frontal system introducing cooler air masses, increased cloud cover, and 50-60% afternoon rain chances that limit solar heating. Seasonal mid-April norms hover at 13-15°C, with model ensembles showing uncertainty from shower timing—drier breaks could nudge toward 16°C, while heavier precipitation caps at 13°C. Hourly observations will refine this as resolution nears.