Recent National Weather Service and model guidance point to Miami International Airport highs in the low 90s on August 21, with the close 26% market-implied odds on 90–91°F versus 92–93°F reflecting uncertainty over the precise timing of the Atlantic sea breeze and afternoon convection. Typical August climatology features an average daily maximum near 89°F, but persistent ridging and above-normal sea-surface temperatures have supported recent readings in the mid-90s; however, scattered thunderstorms—driven by daytime heating and moisture convergence—often develop by early afternoon and limit further warming through cloud cover and evaporative cooling. Traders appear to weigh the risk that stronger or earlier storms could cap the peak at 90–91°F against drier, sunnier conditions that might allow brief excursions to 92–93°F before the sea breeze arrives. Updated NHC and local model runs tomorrow morning will likely sharpen resolution ahead of the 24-hour observation window.