**Cooler northwesterly airflow following a mild 21°C day on October 15 is the main driver positioning 10°C as the market favorite at 51% implied probability.** Official Met Office guidance and ensemble forecasts show a band of rain clearing northward on the 16th, with daytime highs near 15–16°C giving way to clearer skies and strengthening northwest winds. This setup favors radiative cooling overnight, with several guidance runs indicating a minimum of 7–11°C depending on exact cloud cover and wind timing. Historical October averages place the typical low near 8.6°C, and current model consensus clusters around 8–10°C, supporting the heavy weighting on 9–11°C outcomes while leaving room for variance if skies clear earlier than expected.