**Forecasts from the National Weather Service Los Angeles/Oxnard office and multiple models indicate a high in the mid-70s to low-80s for Los Angeles on September 20, 2026, with the most likely range centered near 75–78°F.** Persistent marine-layer stratus and fog, expected to clear only gradually through the afternoon under southwest winds of 10–15 mph, will moderate daytime heating along the coast. This setup, typical for mid-September in the region, limits strong onshore warming and keeps temperatures below the seasonal inland peaks seen earlier in the month. Model consensus shows limited day-to-day variability, but small differences in the precise timing of marine-layer erosion and afternoon wind strength create the spread between 74–75°F and 76–77°F outcomes. Stronger or more persistent onshore flow favors the lower bin, while earlier clearing and lighter winds support the upper one. Historical September climatology for coastal Los Angeles places average highs near 78°F, providing context for why traders heavily weight the 74–77°F range over warmer or cooler extremes. Updated NWS guidance and short-range model runs issued in the next 24 hours will be the key inputs likely to shift positioning before resolution.