Recent numerical weather model runs, including GFS guidance, show Amsterdam's daytime high on October 1 peaking near 19–21°C under overcast skies with light westerly winds and scattered showers, keeping readings close to the historical October average of 17°C but slightly elevated by a mild Atlantic air mass. This narrow range explains the near-even market split between 20°C and 21°C outcomes, as small differences in cloud cover timing, precipitation intensity, or station measurement (such as at Schiphol) can shift the official maximum across the threshold. Traders are weighting the latest observational trends and model consensus, with limited upside potential beyond 21°C due to persistent marine influence and modest insolation.