**Forecast models from multiple sources, including GFS-based outputs and official Polish meteorological summaries, currently indicate a daily maximum of 21–22°C in Warsaw on September 18 under partly to mostly cloudy skies, light southerly winds, and negligible precipitation risk.** This consensus stems from a transitional synoptic pattern: today’s (September 17) cooler, rainy conditions with highs near 18–20°C give way to modest warm advection as a ridge or weaker low-pressure influence allows milder air from the south-southwest. Dew points around 9–12°C and relative humidity dropping into the 50–70% range during peak heating support efficient daytime warming without strong instability or cloud cover that would suppress temperatures. Historical September climatology for Warsaw shows average highs of roughly 18–20°C, so the projected values sit modestly above normal but remain well within typical late-summer variability. Minor model spread exists around exact cloud timing and boundary-layer mixing, which accounts for the small probability mass on 23°C and the negligible odds below 20°C. With resolution occurring within hours, traders are weighting the tight cluster of official and ensemble guidance heavily, producing the observed concentration on 21°C and 22°C outcomes.