Official National Weather Service forecasts and ensemble models show a high near 91–93°F for Houston on September 5, with partly to mostly sunny morning conditions giving way to afternoon showers and thunderstorms. This pattern supports the market’s leading 90–91°F outcome at 41% implied probability, as convective clouds and rain typically cap afternoon peaks in the low 90s during late-summer Gulf moisture regimes. Persistent humidity, light easterly winds, and a 50–60% storm chance further constrain extreme heating. Recent model runs have remained consistent over the past 48 hours, though updated guidance on storm timing or coverage could still shift the exact maximum within the 88–93°F range before resolution.