The warning tiers: CWA issues a
sea warning first (shipping/coastal alert, land still normal), then a
land warning if the storm's track holds — that's the one that matters for you. Land warning doesn't automatically mean closures; it means county/city governments start deciding.
停班停課 (work/school closure): Decided city-by-city, not nationally — Taipei City can close while New Taipei stays open, or vice versa. Under national guidance, a city can call it if the typhoon's edge is expected within 4 hours. Announcements land the night before or by early morning (~5:30–6am) via news, the
CWA site, and local news apps — there's no push alert to a foreign phone, so check the news yourself.
MRT: Elevated/surface sections suspend around sustained winds of Beaufort 7 (~50–61 km/h) or gusts hitting Beaufort 10 — underground sections run longer. In practice: if it's bad enough to close offices, assume the MRT is at least partially down.
THSR / TRA (the Yingge/Daxi day trip's train line): Both cut schedules or suspend outright in a land warning; TRA typically announces the next block of service by ~9pm the night before. If Sep 5 has a system anywhere nearby, check
thsrc.com.tw before heading to the station, not after.
Flights: Airlines usually announce cancellations 24–48hrs ahead of a direct hit. Given the trip's tight Sapporo connection window, a typhoon near either UA1593/UA871 (arrival) or the BR166 Taipei→Sapporo leg is the one scenario worth actually pricing into a plan — check the airline app directly, don't wait for an email.