Forecast model ensembles for coastal Los Angeles on September 5 show a narrow spread centered near 79–82°F, with National Weather Service guidance and private models differing on the timing and strength of onshore marine flow versus daytime heating under clear skies. Recent observations from September 3–4 indicate highs of 75–80°F amid a stable subtropical ridge, keeping the marine layer shallow and limiting rapid warming. Key variables include afternoon wind speeds, dewpoint recovery, and any late-day cloud cover that could cap peak readings, producing the tight market split between the 78–79°F and 80–81°F bins. Updated high-resolution runs and the evening model cycle are expected to refine these thresholds ahead of market resolution.