**Forecast models currently indicate a highest temperature in Warsaw on September 1 most likely between 21–23°C, with the market’s tight distribution between 21°C and 22°C reflecting genuine uncertainty in the timing and extent of cloud cover, precipitation, and westerly flow.** Multiple sources show highs clustered in this narrow range: WeatherBug projects around 22°C with a 50% storm chance, weather25.com and easeweather list 23°C, while Polish and GFS-based outlooks trend slightly lower near 20–21°C under increased westerly winds and scattered rain. This transitional late-summer pattern, following warmer late-August conditions (highs near 25–27°C), features moderate humidity, strengthening west winds, and partial cloudiness that limits diurnal heating. The close implied probabilities highlight how small differences in model runs—such as the exact hour of any showers or thickness of cloud decks—can shift the daily maximum by 1–2°C. Historical September averages for Warsaw (roughly 20–23°C highs) provide context, but the short lead time means the next official updates from European or global models will likely resolve the narrow gap between the leading outcomes.