Forecasts from global and regional models, including GFS and ECMWF runs updated on September 25, point to a maximum of 19–20°C in Amsterdam on September 26 under mostly cloudy skies and northerly winds near 3–4 m/s that limit daytime heating. These conditions align with the market’s near-even split between the two leading outcomes, as small differences in cloud thickness or wind timing can shift the peak by 1°C. Historical September averages near 18–20°C provide context, while current high pressure supports dry but cool advection from the north. Traders will watch the final 24-hour model updates and local KNMI observations for any late adjustments before resolution.