Current forecasts from multiple models indicate an overnight low in Tel Aviv on September 21 around 23–26°C under partly cloudy to clear skies, light to moderate northwest winds, and stable high pressure typical of late-summer eastern Mediterranean conditions. This consensus supports elevated trader focus on the 23°C outcome, as radiative cooling overnight will likely bottom near dawn before daytime heating resumes. Differentiation among close probabilities stems from uncertainty in exact cloud cover, humidity levels near 60–80%, and urban heat island effects that can raise minimums by 1–2°C versus rural baselines. Historical September lows average near 22°C, but recent days have run 1–2°C above normal with minimal synoptic change expected. Updated model runs and official Israeli Meteorological Service guidance before midnight will refine the precise threshold.