Marine layer strengthening and persistent onshore flow from the Pacific are the dominant factors capping downtown Los Angeles highs near 78–79 °F on August 9, according to National Weather Service guidance and recent model runs. These conditions promote low stratus and fog that limit daytime heating, a common summer pattern reinforced by cooler sea-surface temperatures. Recent observations show highs of 84–88 °F earlier in the week before the marine push arrived, shifting trader consensus toward the lower end of the typical August range of 78–85 °F. Heat-advisory expiration on the 9th and ensemble guidance showing minimal warming further support the market-implied odds favoring 78–79 °F over higher bins. Updated NWS forecasts and morning soundings on the 9th will provide the final resolution inputs.