Current ensemble forecasts from the GFS and ECMWF models, aligned with Taiwan Central Weather Administration guidance, project Taipei’s May 18 high near 29–31 °C beneath a strengthening subtropical ridge that favors clear skies, light winds, and strong diurnal heating. This narrow range drives the tightly clustered market probabilities around 30–32 °C, with modest differentiation arising from urban heat-island amplification in the city basin, variable afternoon sea-breeze timing, and small ensemble spread in boundary-layer moisture. Historical mid-May climatology places the typical maximum at 28–30 °C, so any upward model shift or delayed convection could push readings to 32 °C while an earlier sea breeze would likely cap the peak at 29–30 °C. Updated CWA briefings and the next high-resolution model runs tomorrow morning remain the key near-term catalysts.