Overview
For Nov–Dec–Jan (NDJ) 2025/26 expect a typical winter progression with the East Asian continental high (Amihan) increasingly dominant. Cooler conditions and northeasterly winds will influence Taiwan’s weather, with northern and eastern sectors seeing the greatest frequency of showers and frontal rains while western plains trend drier and cooler. Find a vast reduction in Typhoon rates in this interim end of year 2025 at very low risks.
Main Weather Drivers
1. North‑East Monsoon (Amihan)
Role
Northeasterly flow off the cooled Asian continent brings cooler, drier air across the Taiwan Strait. Orographic lifting along Taiwan’s central ranges focuses showers on north & east slopes.
2. ENSO / Tropical Pacific
Role
Weak La Niña–like tendencies increase convection over the Maritime Continent / western Pacific, raising the chance of episodic moisture intrusions and occasional enhanced rain when Pacific convection combines with weakened continental highs.
3. West‑Central Pacific & MJO
Role
Active MJO or convective clusters in the West‑Central Pacific can temporarily amplify rainfall potential for Taiwan — particularly when the NE flow weakens and allows moisture to advect north.
4. Subtropical Jet / Mid‑latitude troughs
Role
The latitude and strength of the subtropical jet determine whether frontal systems and troughs dig south into Taiwan’s latitude. A southward STJ increases frontal intrusions and more protracted rain events.
Transition: SW Monsoon → Wind‑shift / Amihan
The end of the southwest (summer) monsoon is a gradual wind‑shift. As the Asian landmass cools, the large continental high strengthens and surface winds move from southerly to northeasterly. Expect mixed conditions in the transition window: residual convective bursts from the south overlapping with incoming cool, showery NE winds. Once Amihan is established, the pattern becomes more zonally consistent — drier on western plains and showery on northern & eastern coasts.
Regional Expectations (NDJ 2025/26)
- Northern & Eastern Taiwan: most frequent cloud and shower days; orographic enhancement produces the highest rainfall totals and occasional prolonged frontal rains.
- Western lowlands (Taoyuan → Kaohsiung): generally drier and cooler; pleasant sunny spells when Amihan strong, but intermittent heavy rain possible during frontal or Pacific convective episodes.
- Central Mountains: wettest sector; highest flood / landslide potential during strong frontal/cold‑surge events; occasional snow at the highest summits during the coldest surges.
- Marine / Taiwan Strait: stronger NE winds and rough seas during cold surges — monitor marine advisories.
Uncertainties & What to Monitor
Key uncertainties include the exact strength of the continental high (Amihan), the latitude of the subtropical jet, and the timing/intensity of Pacific convective pulses (MJO / clusters). These factors will determine how many wet episodes Taiwan experiences and where they concentrate. Monitor national weather agency bulletins and operational model updates for changes to risk timing.