Latest ECMWF and KNMI ensemble runs for August 17 show modest high pressure with light southerly flow and variable cloud cover supporting daily maxima centered near 21–22 °C, consistent with the market’s tight clustering at those levels. Sea-surface temperatures around 18 °C limit daytime warming while weak Atlantic fronts could increase low-level moisture and reduce insolation enough to cap readings at 20 °C or allow brief clearing that pushes toward 23 °C. Short-range model spread remains 1–2 °C because boundary-layer mixing and exact frontal timing are still sensitive to small initialization differences; traders are therefore weighting the most recent 00Z and 12Z guidance that keeps the mode in the low-20s while acknowledging the realistic tail risk of a cooler or warmer outlier.