**Persistent summer heat and high humidity across Southeast Texas have driven strong trader consensus toward an overnight low of 78–79°F in Houston on August 21, 2026.** Official forecasts from the National Weather Service and AccuWeather show a heat dome maintaining clear skies and elevated dew points, producing typical August minimum temperatures near the long-term average low of 77–78°F. With highs expected near 100°F and minimal cooling overnight, the lowest reading is projected to settle in the upper 70s rather than dipping into the mid-70s or lower. This positioning aligns with climatological norms for the period, when Gulf moisture and urban effects limit radiative cooling. The 93.5% market-implied probability for 78–79°F reflects traders’ assessment of stable atmospheric conditions and the low likelihood of significant deviations on this date. Realistic challenges to this outcome would require an unexpected increase in cloud cover, scattered showers, or a stronger-than-forecast sea breeze to enhance nocturnal cooling—developments not supported by current model consensus. Updated NHC or local NWS guidance could shift odds if conditions evolve differently by evening.