Latest National Weather Service and model consensus forecasts for Houston on May 18 project a daily high near 86–88°F, driven by a southerly flow of Gulf moisture under weak high pressure that limits cloud cover and allows strong daytime heating. This aligns with the climatological normal of 88°F for mid-May at Houston Intercontinental Airport, where average highs climb from 82°F early in the month to near 89°F by month-end. Current ensemble runs show minimal spread, with only modest cooling possible from scattered afternoon showers; the 53% market-implied probability for 88°F or higher reflects traders’ assessment that typical May warming plus favorable steering patterns favor the upper end of the range, though any shift in the subtropical ridge could pull readings into the mid-80s.