Recent official forecasts from the Finnish Meteorological Institute and ensemble models indicate a highest temperature near 16–17°C on September 14 under light northwesterly flow and partly cloudy skies, consistent with mid-September climatology at Helsinki’s latitude where Baltic Sea moderation typically caps daytime maxima around 15.7°C. Trader sentiment favoring 21°C or higher at 50% implied probability likely reflects residual uncertainty in 48-hour model runs, potential for stronger southerly advection, or clearer conditions enabling greater insolation, despite limited warm-air transport signals in current guidance. Historical analogs show occasional spikes above 20°C but remain uncommon this late in the season, while lower bins around 13–19°C capture the bulk of ensemble spread. Updated model output and FMI briefings over the next 24 hours represent the key near-term catalysts that could shift these market-implied odds.