Recent Met Office guidance and ensemble model runs point to a stable high-pressure regime over southern England through early July 2026, supporting daytime highs near 27 °C and overnight radiative cooling that favors minimum temperatures of 15–17 °C. This setup, combined with light winds and moderate humidity, explains why the market clusters tightly around 13–15 °C: small differences in cloud cover, boundary-layer mixing, or the precise timing of the daily minimum can shift the recorded low by 1–2 °C. London’s urban heat-island effect adds further variability, as denser built-up areas retain warmth longer than suburban stations used for official readings. With only 48 hours until resolution and limited model spread in the short-range forecasts, traders assign comparable implied probabilities to the leading outcomes while discounting extremes below 12 °C or above 18 °C.