Forecast models indicate the lowest temperature in Helsinki on September 9 will likely fall in the 12–15°C range, driven by a mild southwesterly maritime air mass from the Baltic Sea, where surface waters remain near 14°C. Persistent cloud cover and light winds overnight will limit radiative cooling, while scattered showers add humidity that further moderates minimums. These conditions contrast with clearer, calmer nights that historically allow drops toward the 10°C climatological average low. Minor model spreads in wind speed and cloud timing explain the tight clustering of market-implied odds around 13–14°C, with any late clearing potentially pushing readings lower. Updated runs from agencies like the Finnish Meteorological Institute will refine the exact threshold ahead of resolution.