Latest numerical weather prediction ensembles from the Finnish Meteorological Institute and European models place the most likely daily maximum in Helsinki on August 17 near 20–21 °C, with the narrow 1.5-percentage-point edge for 21 °C reflecting modest warm-air advection and reduced cloud cover in the latest runs. Typical late-summer Baltic Sea moderation, light westerly flow, and variable daytime insolation create the tight clustering around these thresholds, while small shifts in timing of any showers or thickness of low-level cloud can easily swing the peak by a degree. Historical August maxima average near 19 °C, so current guidance sits slightly above climatology but well within normal interannual variability. Updated model cycles and observational data over the next 24 hours will likely refine the distribution before resolution.