Traders assign closely matched probabilities across 19–22°C for Cape Town’s August 4 maximum because short-range forecast models show modest uncertainty in the strength of onshore flow from the cool Benguela Current and the timing of any high-pressure ridge that could enhance solar heating. August climatology centers on 17°C daytime highs with frequent marine-layer cloud and westerly winds that suppress temperatures, yet brief clear spells or lighter winds can add several degrees. Official South African Weather Service guidance and ensemble runs will clarify whether conditions trend toward the upper or lower end of the typical winter range ahead of market resolution.