**Forecast consensus positions mid-to-upper 60s as the most likely range for Los Angeles’ minimum temperature on September 20, 2026.** Official National Weather Service guidance and multiple model outputs indicate an overnight low near 65–69 °F at primary reporting stations such as Los Angeles International Airport, with the 68–69 °F bin carrying the highest market-implied probability (40 %). This aligns with a typical late-September marine-layer pattern in which onshore southwest flow and increasing cloud cover limit nocturnal radiative cooling. Key drivers include persistent low-level moisture and stratus that moderate temperature drops, preventing the sharper declines sometimes seen under clear, calm conditions. Historical averages for the date hover around 63 °F, but current model runs and NWS point forecasts trend several degrees warmer due to the cloudy regime. Recent updates show little day-to-day shift in guidance, keeping probabilities concentrated in the 64–69 °F outcomes while lower bins (below 64 °F) remain discounted absent a stronger offshore or clear-sky signal. Traders are therefore weighting the near-term forecast stability and the limited upside or downside variance expected before the 24-hour period resolves.