Recent National Weather Service guidance and ensemble model consensus point to a Houston high temperature near the seasonal normal of 88°F on May 18, driven by persistent southerly flow under a weak ridge and limited cloud cover that supports strong daytime heating. This setup keeps the market’s leading 88°F-or-higher outcome at 47.5 percent while the combined 86–87°F bin holds 32 percent, reflecting modest uncertainty from possible scattered afternoon convection. Historical analogs from mid-May show similar patterns rarely exceeding 90°F without stronger ridging, and the absence of any tropical moisture surge or cold-front passage supports the current implied probabilities. Updated GFS and NAM runs expected later today will provide the next key data point for traders.