Persistent warm, humid maritime tropical air over South Florida is anchoring forecast overnight lows near 80°F for Miami on August 3, aligning with National Weather Service guidance and the market’s leading 80-81°F bin at 38.5% implied probability. High dew points and limited nocturnal radiative cooling under partly cloudy skies with scattered convection suppress drops below the seasonal average of roughly 78°F. Recent model runs show minimal variability, with most guidance clustered between 78–82°F and no approaching cold front or tropical system to alter the pattern. Traders therefore assign the highest odds to the narrow 80-81°F range while discounting cooler or warmer outliers that would require atypical steering or moisture changes before resolution.