Recent forecast model runs from the Met Office and European Centre for Medium-Range Weather Forecasts show high uncertainty in overnight radiative cooling over London for July 24, with clear-sky potential allowing lows to dip toward or below 13°C while cloud cover or residual warmth from recent heatwave dissipation could hold them near 16–17°C. This explains the tight clustering of market-implied odds between 13°C or below (46.5%) and the 15–17°C range (35–37%), reflecting genuine variability in boundary-layer conditions and wind patterns rather than strong consensus. Historical July climatology places average London lows near 14–15°C, providing context for why traders assign low probability (under 2%) to outcomes above 20°C. Updated model guidance expected within 24–48 hours could shift resolution thresholds tied to official minimum temperature readings.