Trader consensus on Austin's August 21 overnight low centers on the mid-to-upper 70s because National Weather Service and model guidance indicate persistent high pressure, light southerly winds, and clear to partly cloudy skies that limit radiative cooling. Typical August minima near 75°F provide climatological context, while current dew points in the low 70s and urban heat retention slow the temperature drop after sunset. The tight clustering of probabilities across 72–81°F ranges reflects minor model disagreements on exact wind mixing and cloud timing, which can shift the minimum by a few degrees. Official resolution will use the lowest hourly observation at the primary Austin reporting station before sunrise on the 22nd.