Trader sentiment clusters tightly around 19–20°C for Warsaw’s September 14 maximum, reflecting short-range ensemble spreads in leading models where daytime highs hover near the 18–20°C September climatological average. Primary differentiation stems from uncertainties in low-level cloud cover, which modulates incoming solar radiation, and boundary-layer mixing under light westerly flow; modest increases in cloud or shifts in advection of cooler maritime air can cap the peak 1–2°C lower, while clearer conditions allow brief radiative warming. Official guidance from regional centers shows limited spread at this lead time, yet the market’s near-even split between 19°C and 20°C captures residual model disagreement on exact timing of any weak frontal passage. New model cycles and observational updates over the next 24 hours remain the key catalysts for shifts.