Latest Met Office guidance and ensemble model runs point to a London high of 25–26 °C on August 7, underpinning the market’s near-even split between those two outcomes. Subtle differences in afternoon cloud cover, boundary-layer mixing, and the strength of the southeasterly flow will decide whether the peak reaches the upper end of that range. The urban heat-island effect at central stations can add 1–2 °C relative to Heathrow, while any late-day sea-breeze or increased low-level moisture would cap readings nearer 25 °C. With resolution only 48 hours away, the next 12-hour model cycles and updated Met Office briefings will sharpen the distinction between these tightly matched probabilities.