Current official guidance from the Finnish Meteorological Institute and other models shows a peak around 19–20°C on August 18 under southwesterly flow, partly cloudy skies, and Baltic Sea moderation that limits daytime heating. Ensemble spreads and recent runs introduce modest upside risk to 21°C if daytime insolation increases or warm advection strengthens slightly, while greater cloud cover or earlier frontal passage could cap the maximum at 19°C. Traders assign the highest probabilities to the 20–21°C outcomes because short-range model uncertainty at this lead time centers on boundary-layer mixing and local radiative effects rather than large-scale pattern shifts. Historical August maxima in Helsinki cluster near 18–20°C, providing context for the tight clustering of market-implied odds.