Taiwan Typhoon Warnings Explained (Sea Warning, Land Warning, Typhoon Day)
Taiwan has two typhoon warnings and one day off, and almost every visitor learns them in the wrong order. They hear that a warning has been issued, assume the island is shutting, and then spend a perfectly ordinary afternoon wondering when something is going to happen.
The two warnings are not two levels of the same thing. They describe two different pieces of geography, they are issued at different times, and only one of them has much to do with whether you can leave your hotel.
And the thing everybody actually wants to know, whether tomorrow is a day off, is not decided by the weather service at all.
Photographs here are stock images for illustration and are not pictures of the events described.
The Sea Warning comes first and most people ignore it
The Central Weather Administration issues a sea warning roughly twenty-four hours before a typhoon's gale-force wind radius is expected to reach waters within 100 kilometres of Taiwan, Kinmen or Matsu. Gale force here means Beaufort 7, about 30 knots, which is the same threshold most agencies in the region use to draw the outer ring of a storm.
Notice what is being measured. Not the eye, not the centre, not the point of closest approach. The outer edge of the storm's wind field, and its distance from the coast rather than from land. A typhoon can trigger a sea warning while its centre is still several hundred kilometres away and forecast to miss the island entirely.
That is why the sea warning feels like a non-event on shore. The sky is normal, the shops are open, and the warning is genuinely aimed at somebody else. It is a shipping and fishing alert, and it is doing its job even when nothing happens to you.
What it does do is start the machinery. Ferry operators begin cancelling, airlines start opening flexible rebooking windows, and the outlying islands lose their connections first. If your plans involve Penghu, Green Island, Orchid Island, Xiaoliuqiu, Matsu or Kinmen, the sea warning is your warning, not the land one.
The Land Warning is the one that changes your day
The land warning comes about eighteen hours before that same gale-force radius is expected to touch land. Six hours later than the sea warning, and roughly one working day before anything happens to you.
Both warnings are updated at least every three hours once issued, and the interval tightens as the storm closes in. The bulletin page moves to something closer to hourly when a system is near. If you are watching a storm, that update rhythm is a better signal of seriousness than the wording of any single bulletin.
The land warning is the trigger for the rest of the country. Highway agencies start planning closures, rail operators begin publishing reduced timetables, and the county and city governments start working out what to announce that evening.
It is worth being clear about what the land warning is not. It is not a statement that your town will be hit. Taiwan is 394 kilometres long with a mountain range down the middle, and a land warning covering the island can mean a battering in Hualien and drizzle in Taichung. The warning covers the storm's reach, not its damage.
A Typhoon Day is decided by your mayor, not by the CWA
This is the part that surprises people. The weather service does not close anything. It supplies forecasts and rain and wind guidance to local governments, and each city and county head then decides independently whether to suspend work and classes in their own jurisdiction.
The criteria they work from are specific. A suspension is justified when an area is forecast to fall inside the storm's wind radius within the next four hours with average winds of 14 metres per second or more, about 50 kilometres per hour, or gusts of 25 metres per second, about 89 kilometres per hour. It is also justified on rainfall alone, at 350 millimetres in lowland areas or 200 millimetres in the mountains, where a disaster has already happened or looks likely.
There is a third clause that covers everything else. If terrain or rainfall has cut transport, water or power in a way that makes getting to work or school unsafe, that is grounds on its own, regardless of the wind numbers.
Because the decision is local, the map goes patchy. Neighbouring cities coordinate within shared commuting zones so that somebody living in Taipei and working in New Taipei is not caught between two different answers, but you will still see one county closed and the next one open on the same morning.
Announcements covering the following morning generally land the night before, between seven and ten in the evening. That window is worth knowing, because it is the difference between finding out in time and finding out at the station. The consolidated official list is published at https://www.dgpa.gov.tw/typh/daily/nds.html
What actually stops, and in what order
Typhoon Bavi in July gave a clean sequence. Ferries went first, with 116 sailings cancelled across 13 routes, including the outlying island services and the cross-strait links. Then aviation, with more than 1,200 flights cancelled and every international departure and arrival at Songshan, Taoyuan and Kaohsiung scrapped for a full day.
The order matters more than the totals. Ferries stop early because a small vessel in a rising swell is dangerous long before an airport becomes unusable. Flights stop later but recover more slowly, because aircraft end up in the wrong cities and the backlog has to be flown out over the following days.
Ground transport is the odd one out. Metro systems generally keep running, rail services usually thin out rather than stop outright, and the thing that actually strands people is the highway network rather than the trains.
Shops and restaurants follow the suspension announcement rather than the weather. In a city that has been closed for the day you will find convenience stores open and very little else. That is the practical reason a day off in a typhoon is duller than it sounds.
The warning lifts before the roads reopen
The land warning is cancelled once the gale-force radius has moved off the island, and the sea warning is cancelled after that. Both can be lifted on a bright morning, and both routinely are.
The mountains do not follow that schedule. The Suhua Highway on the east coast and the Central Cross-Island Highway close for days after a serious storm while crews clear landslides, and the reopening is announced by the highway authorities rather than by the weather service. If your itinerary crosses the island or runs down the east coast, that is the number to chase, not the warning status.
This is the same gap that catches people everywhere in the region. The alert is a forecast product and it ends when the forecast condition ends. The disruption is a physical problem and it ends when somebody has moved the rock off the road.
For planning purposes the honest summary is short. A sea warning means check your ferry. A land warning means check the evening announcement. A day off means stay where you are and expect a quiet, slightly boring day indoors. And the morning after the all-clear, check the roads before you check the sky. Current bulletins in English are at https://www.cwa.gov.tw/V8/E/
What I find genuinely sensible about the Taiwanese setup is that it keeps the forecast and the decision in separate hands. The weather service says what the storm will do and stops there. Somebody elected in your city decides what that means for your Monday, and has to answer for it if the call goes wrong in either direction. It produces some inconsistent mornings, and it also means nobody sitting in Taipei is deciding whether Hualien goes to work.
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