Miami's overnight minimum temperatures in mid-August typically range from 78–82°F due to high humidity, elevated dew points, and limited radiative cooling under subtropical conditions. Current National Weather Service guidance and ensemble model runs point to lows near 80–81°F on August 11, with the market's tight clustering around 78–83°F reflecting uncertainty in cloud cover, sea-breeze timing, and any scattered thunderstorm activity that could trap heat or enhance mixing. Clearer skies would favor the lower bin through greater nocturnal cooling, while increased moisture and light winds support the higher end. Traders weigh these variables against historical August climatology showing rare excursions below 76°F absent unusual frontal passages.