**Forecast uncertainty around a potential cold-air advection and radiative cooling overnight is balancing trader odds near 50% for both sub-1°C and 11°C+ extremes on the October 17 minimum in Helsinki.** Multiple models show a high near 12–13 °C under initially mild southwesterly flow and showers, followed by a shift to northerly winds that could drop the overnight low to 2–6 °C, with clearer skies enhancing surface cooling. Historical October averages place the typical low near 4 °C, but recent model runs differ on the exact timing of the frontal passage and cloud dissipation, keeping the distribution broad. Finnish Meteorological Institute and ECMWF guidance updates in the next 24–48 hours will likely tighten the range ahead of the market’s resolution.