Forecast models from agencies including the Finnish Meteorological Institute and ECMWF indicate partly cloudy skies with light southerly flow over Helsinki on September 28, supporting afternoon highs of 15–16 °C under building high pressure. Recent runs show modest warming from adiabatic compression and reduced cloud cover during peak insolation, yet persistent marine influence and variable boundary-layer mixing keep temperatures from exceeding this narrow band. Hourly guidance peaks near 15 °C in several ensembles with limited upside to 16 °C if clearing occurs earlier; downside risk remains low absent unexpected frontal passage. Trader consensus reflects this tight scientific spread, with resolution hinging on the precise maximum recorded at official stations before midnight local time.