Current ensemble forecasts for Taipei indicate a likely daily high near 30–31°C on May 18, driven by seasonal warming as the East Asian monsoon transitions and subtropical high pressure builds over the region. Meteorological models show modest spread from variable low-level moisture and intermittent cloud cover typical of the plum-rain onset period, which can suppress afternoon peaks by 1–2°C or allow brief clearing to push readings toward 32°C. Official climatological normals place mid-May maxima at 28–29°C, so any departure hinges on precise steering of weak disturbances and boundary-layer mixing; traders appear to price this narrow uncertainty band by clustering probabilities tightly around the 30–32°C outcomes while assigning lower weight to more extreme deviations.