**Forecast models indicate Shanghai's overnight low on October 13 will likely settle near 20–21 °C, with trader consensus tightly clustered around 20–22 °C due to subtle differences in radiational cooling estimates.** Clear to partly cloudy skies and light northerly winds overnight support modest surface cooling under stable high pressure, while urban heat retention and moderate humidity (around 70–85 %) limit further drops. Official guidance from sources like Open-Meteo and local forecasts shows the minimum occurring near dawn at 19–21 °C, with hourly trends bottoming around 19–20 °C before sunrise. The narrow spread among leading outcomes reflects uncertainty in exact boundary-layer cooling rates and microscale urban influences rather than any major synoptic shift, keeping probabilities for outcomes below 19 °C very low.