Near-term forecast uncertainty for London's overnight minimum on July 20 is driving closely matched market odds across 10–17°C, as short-range models from the Met Office and ECMWF show a range of possible synoptic setups. A potential Atlantic trough or increased cloud cover could limit radiative cooling and keep lows near or above 14–16°C, while clearer, calmer conditions under high pressure would favor stronger nocturnal cooling toward 11–13°C or lower. Historical July climatology places typical London minima around 13–15°C, but current model spread and steering flow variability explain why traders assign roughly equal implied probabilities across several outcomes. New 00Z and 12Z model runs, plus updated Met Office guidance expected within 24–48 hours, will likely refine the temperature range and shift positioning.