Recent National Weather Service guidance and ensemble model runs indicate a highest temperature for Los Angeles on August 20 most likely in the upper 70s to low 80s, driven by a persistent marine layer and onshore flow from the Pacific that caps daytime warming along the coast. This setup produces a strong temperature inversion, with cool, moist air trapped below roughly 1,000–2,000 feet, delaying clearing and limiting surface heating even under weak upper-level ridging. Traders see broad uncertainty across the 75–83°F bins because small differences in inversion strength, wind speed, or exact clearing time can shift the peak by several degrees; historical August analogs show coastal highs rarely exceed 85°F without strong offshore flow. Updated model cycles and afternoon observations tomorrow will refine the range.