National Weather Service and private model guidance for Houston on August 20 project a high near 98–99°F under mostly sunny skies and light southerly flow, driving the market’s 53.5% implied probability on that bin. Persistent late-summer heat-dome conditions across Southeast Texas, combined with suppressed cloud cover and minimal precipitation, support strong daytime heating while Gulf moisture keeps heat indices elevated. Recent runs show limited day-to-day variability, with only modest spread between 97°F and 101°F across ensembles; any unexpected increase in afternoon convection or slight wind shift could trim the peak by a degree or two, while clearer conditions or stronger subsidence would favor the 100–101°F outcome currently at 23%. Traders are weighting the consensus forecast heavily given the proximity to resolution and historical August climatology centered in the mid-90s.