Recent numerical weather prediction ensembles from global models indicate the minimum temperature in Warsaw on September 19 will likely fall between 11–13 °C under building high pressure, light southwesterly flow, and mostly clear to partly cloudy skies that permit moderate overnight radiational cooling. Trader sentiment remains closely balanced near 50 % for both sub-7 °C and 16 °C-plus outcomes because small differences in cloud timing, boundary-layer mixing, or slight shifts in the steering flow can alter the nocturnal minimum by several degrees. Historical September climatology for the city shows typical overnight lows near 10–12 °C, providing context for why current guidance clusters in the middle bins while leaving room for tail scenarios if models diverge on the strength of the high or residual moisture. Updated runs from the ECMWF and GFS ensembles over the next 24–48 hours will be the key data releases likely to refine these probabilities.