Forecast models from the National Weather Service and other agencies indicate San Francisco's overnight low on October 13 will settle in the low to mid-50s°F under clear skies and light northeast-to-northwest winds, supporting the tight clustering of market probabilities around the 50–55°F bins. Radiative cooling after sunset, modulated by the marine influence and a stable high-pressure ridge, drives the minimum temperature, with dew points near 49–52°F limiting further drops. Slight variations in urban heat island effects across observation sites or minor forecast adjustments in the final model runs could shift the exact reading between adjacent 2°F intervals. Updated NWS guidance and real-time station data through the morning will refine trader assessments ahead of market resolution.