Marine layer persistence and onshore flow from the Pacific represent the dominant drivers behind trader consensus favoring 72–73°F as the leading outcome for Los Angeles’s July 4 high, with implied probability at 37%. National Weather Service guidance highlights morning patchy fog and extensive low clouds that suppress daytime heating, consistent with recent model runs showing limited afternoon clearing and light westerly winds. This pattern aligns with typical early-July climatology along the coast, where marine influence caps highs below seasonal averages near 78°F. Minor upward shifts in some ensemble members reflect potential for partial clearing, supporting the secondary 74–75°F bin, while probabilities drop sharply above 77°F absent stronger offshore flow. Updated NWS briefings and next model cycle remain the key near-term catalysts.