TCCOR Levels Explained (TCCOR 5, TCCOR 1, All Clear)
If you live near a US base in Japan, or you are married to somebody who does, you will hear a number before you hear a storm name. The base is at 3. We just went to 2. Nobody says which typhoon.
The scale is called TCCOR, Tropical Cyclone Conditions of Readiness, and it runs backwards from how most people expect. Five is calm. One is the storm. There are three separate versions of One, and then there is a fourth thing after them that is not a number at all.
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.
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