TCCOR Levels Explained (TCCOR 5, TCCOR 1, All Clear)

Most alert scales count upward as the danger rises. TCCOR counts down, and it counts hours rather than severity — which makes it the rare system where the number tells you how much time you have left rather than how bad things are.

That is genuinely useful if you are trying to plan a day, and it is why the scale is worth reading even if you have no connection to a US installation. Every level on it is a statement about one threshold: destructive winds of 50 knots, and how many hours away they are.

Photographs here are stock images for illustration and are not pictures of the events described.

What TCCOR actually measures

Every level is defined against one specific wind speed, and knowing it makes the rest of the scale obvious.

Destructive winds means 50 knots sustained, or gusts of 60 knots. In miles per hour that is about 58. That is the threshold the entire system is built around, and it is not a typhoon threshold. A storm can be a typhoon and never produce 50 knots at your particular location, and the base will run its readiness levels off what is forecast for that location rather than off the storm's grade.

So each level answers one question: how many hours until destructive winds could arrive here.

That is why the numbers descend. They are a countdown, not a severity rating. A base at TCCOR 3 is not experiencing worse weather than a base at TCCOR 4. It is closer in time.

This single fact clears up most of the confusion people have with the scale, including mine when I first encountered it.

TCCOR 5 and the clock that runs backwards

Here is the full ladder, with the hours attached.

TCCOR 5 means destructive winds are possible within 96 hours. TCCOR 4 is 72 hours. TCCOR 3 is 48 hours. TCCOR 2 is 24 hours. TCCOR 1 is 12 hours.

Four days, three days, two days, one day, half a day. Each step roughly halves the time you have left, which is a sensible way to build a warning system because the things you are supposed to do get shorter as you go.

At the top of the ladder the instruction is to stock up and hold supplies. At the bottom it is to stay inside.

One oddity worth knowing: TCCOR 5 is described as the level used outside normal typhoon season. It is the resting state for the months when a storm reaching the island would be unusual. During the season itself the resting state is different, which brings us to the part that confuses almost every newcomer.

Why Okinawa sits at 4 all summer

From 1 June to 30 November, Okinawa stays at TCCOR 4 unless directed otherwise.

Read that again, because it changes how you should interpret the number. TCCOR 4 for six months of the year is not a warning about anything. It is the baseline. It means the season is open, keep 72 hours of supplies in the house, and get on with your life.

People who have just arrived see 4 on the sign at the gate, assume something is coming, and start buying water. Then they see 4 again three weeks later and stop believing the system entirely. Both reactions come from reading a default state as an alert.

The number that means something is 3. That is the first level in the season that had to be declared, by a person, about a specific storm. When Okinawa goes to 3 there is something real out there and it is two days out.

This is also why the searches I see for TCCOR 4 meaning tend to come from people who are quietly worried and did not need to be, while the ones for TCCOR 2 are usually people who have already worked out that the shops will be shut tomorrow.

TCCOR 1 splits into three

The bottom of the ladder is not one condition. It is a sequence, and the distinction matters because two of the three feel identical from indoors.

TCCOR 1 Caution means winds of 35 knots are already occurring and destructive winds are anticipated within 12 hours. Things are moving. It is not yet dangerous to be outside, but the window for doing anything outdoors is closing.

TCCOR 1 Emergency means destructive winds are occurring right now. Outdoor movement is prohibited. Stay indoors and away from windows. This is the actual storm, and it is the only level where the instruction is about your body rather than your schedule.

TCCOR 1 Recovery means the destructive winds have subsided and are no longer forecast. Outdoor movement is still prohibited. Essential base recovery is under way, meaning crews are out checking for downed lines and blocked roads while everybody else stays put.

That third one is the one people get wrong. Recovery sounds like the all-clear and it is not. The wind has dropped and the hazard has changed rather than ended, because now the danger is what the wind left on the ground. Somebody standing on a wet road under a damaged power line during Recovery is in a genuinely worse position than they were an hour earlier.

All Clear is not the same as over

All Clear is the final state, and it is declared when destructive winds have passed, are no longer forecast, and recovery efforts are considered complete.

Note the second half of that. It is not a weather statement alone. It is also an operational one. The island can be sunny and calm for hours before All Clear is given, because somebody still has to walk the flight line and clear the roads and confirm the water is running.

For anybody planning around a base, this is the number that decides when normal life resumes. Not the moment the storm leaves. The moment the paperwork catches up with it.

And that gap is where a lot of frustrated phone calls happen, especially from people trying to work out whether their flight, their appointment or their delivery is happening. The weather has visibly finished. The condition has not been lifted. Both things are true at once.

Current conditions are broadcast on AFN television and radio, and the underlying forecasts come from the Joint Typhoon Warning Center. If you are near Kadena, the base weather page carries the current level.

The thing I find genuinely well designed about TCCOR is that it separates timing from severity, which almost no public warning system does. A civilian typhoon bulletin tells you how strong the storm is and leaves you to work out when it matters to you. This one tells you when, and lets the strength take care of itself.

What TCCOR 1-E actually looks like on the ground

The levels are a forecast ladder, and the one that changes daily life is not a forecast at all. TCCOR 1-E, Emergency, means destructive winds of at least 58 mph are occurring now.

At 1-E, outdoor activity is prohibited except for lifesaving measures. That is not a recommendation. Installations close, gates restrict movement, and personnel are expected to be inside and to stay inside until the level is lifted. A large, slow-moving system holds 1-E far longer than a compact fast one, because the 58-knot threshold is exceeded over a wider area for more hours — the difference between a storm that is through in an afternoon and one that pins an island for most of a day.

The step that follows is easy to misread. TCCOR 1-R, Recovery, means winds of 50 knots or greater are no longer forecast and damage assessment can begin. It is not the all clear. Crews are out precisely because the situation is still unresolved, and debris, standing water and downed lines are at their worst in that window.

It is worth watching even if you have nothing to do with the military. The bases and the civilian island run on the same weather, and installation decisions are published in English on a fixed schedule, which is more than can be said for most of what a visitor can find. When Okinawa goes to TCCOR 1, airline cancellations for the following day tend to follow within hours — not because the airlines are reading TCCOR, but because both are responding to the same forecast. For an English-speaking traveller trying to work out whether tomorrow is lost, the TCCOR number is often the earliest clear signal available.

Reading TCCOR as a civilian on Okinawa or in mainland Japan

The Japanese warning system and the TCCOR system run side by side over the same islands, and they answer different questions. JMA tells you what the storm is doing. TCCOR tells you what a large organisation has decided to do about it, on a fixed timetable, in English.

That last part is the practical value. JMA's detailed products are thorough and are published in Japanese first; the English versions are narrower. TCCOR levels are announced in English by the installations, they change on a schedule published in advance, and they are picked up quickly by local English-language channels. For a visitor who cannot read a Japanese bulletin at speed, the TCCOR level is frequently the earliest clear signal available.

The alignment is not exact and should not be treated as a translation. TCCOR is a readiness decision for a specific set of installations, and it is deliberately conservative: it moves early so that preparation happens while it is still safe to be outside. A move to TCCOR 2 does not mean JMA has issued a warning, and TCCOR going to 1 does not mean the civilian island is closing. What it does mean is that somebody with good forecast access has concluded destructive wind is inside twelve hours, and that conclusion is usually followed by airline decisions within a few hours.

The baseline is the part outsiders get wrong most often. Okinawa installations sit at TCCOR 4 for the entire season by default, regardless of whether anything exists in the Pacific. Seeing TCCOR 4 in September is not information. TCCOR 3 is the first level that means something specific, and it is the one to act on if you have anything flexible in your plans.

There is also a mainland dimension that gets less attention. Installations in Kanagawa, Tokyo, Aomori and elsewhere run the same scale, so a typhoon tracking up the main islands produces TCCOR movements far from Okinawa. If you are in Tokyo and cannot easily follow the Japanese-language detail, a mainland installation moving to 2 is a clean, early, English-language indicator that the storm is being taken seriously locally.

The limits are worth stating. TCCOR says nothing about rainfall, nothing about landslides, and nothing about the railway — and in mainland Japan the railway is what actually determines whether your day works. JR East and JR West announce planned suspensions a day ahead on their own logic, which is rainfall- and wind-based but not tied to TCCOR at all. Use TCCOR as the early bell, then switch to the railway announcements for the decision.

TCCOR translated into civilian decisions

The official definitions describe readiness conditions for installations. This is the same ladder rewritten for somebody who does not work on a base.

Level	Wind within	What a civilian should do
TCCOR 4	72 hours	Nothing. This is the seasonal default from June to November.
TCCOR 3	48 hours	First level that carries information. Check flights, move flexible plans, buy food.
TCCOR 2	24 hours	Assume tomorrow is lost. Airline cancellations usually post around now.
TCCOR 1	12 hours	Be where you will stay. Shops will close and stay closed.
TCCOR 1-E	Happening now	Indoors. Nothing is open.
TCCOR 1-R	Wind easing	Not the all clear. Debris and downed lines are at their worst. Stay in.
All Clear	—	Naha usually resumes within half a day. Ferries take a day or two longer.

The two rows worth memorising are TCCOR 3, because it is the first one that carries information, and TCCOR 1-R, because it is the one people misread as the end.

Warning systems by region

This page is part of a series that takes each warning system in the western Pacific on its own terms rather than translating them into one another.

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