**Forecast uncertainty for Moscow’s overnight low on September 18 centers on variable cloud cover, light rain, and weak advection amid a mild late-summer pattern.** Official guidance and ensemble models show overnight temperatures most likely settling between roughly 10–13 °C, with daytime highs near 16–18 °C, consistent with climatological norms for mid-September. Cloudiness and showers expected overnight limit radiative cooling, while light southwesterly flow prevents strong cold-air advection that could push readings toward 5 °C or below. Conversely, any early clearing or drier air would cap the minimum well short of 15 °C. Trader consensus at 46.5 % for each tail outcome reflects this model spread and the narrow window for resolution, with specific-temperature contracts clustered around 20–21 % underscoring the difficulty of pinpointing the exact minimum under transitional autumn conditions. Updated model runs and surface observations over the next 24 hours will be the key catalysts.