High pressure building across southern England is driving expectations for peak temperatures near 35°C in London on August 13, with Met Office guidance and recent model runs favoring maxima of 34–36°C under mostly sunny skies and light winds. The spread in market-implied odds across 34–37°C reflects typical ensemble uncertainty in short-range forecasts, where small shifts in cloud cover, timing of any Atlantic moisture, or local urban heat effects could alter the daily high by 1–2°C. Recent warming trends this week, with highs already climbing into the low 30s, support the current trader consensus around these central outcomes while underscoring the potential for brief afternoon relief if scattered showers develop.