Forecast models from agencies including the Finnish Meteorological Institute and global ensembles show a high near 16°C in Helsinki on September 29, 2026, under mostly cloudy skies with southwesterly flow and light winds near 3–5 m/s. Current surface observations at Helsinki-Vantaa Airport hover around 15°C midday, consistent with seasonal norms where the long-term average high is 12.7°C and the all-time record stands at 17.9°C. This strong model consensus and real-time data underpin the 99.9% market-implied probability for 16°C. A realistic shift could occur if unexpected clearing allows greater insolation or if a late surge of cooler maritime air drops the peak below 15°C, though such deviations remain low-probability given stable high pressure.