If you have planned a trip around a Japanese typhoon forecast, you may have noticed something without naming it: everyone is saying the same thing. The hotel, the railway, the app on your phone and the television all describe the same storm, arriving at the same time, with the same track.
That is not luck, and it is not a national talent for meteorology. Forecasting in Japan is a licensed activity. You need permission from the Director-General of the Japan Meteorological Agency to run a forecasting business at all — and even taking measurements you intend to publish is bound by technical standards.
Forecasting requires permission
The provision is direct. A person other than the Japan Meteorological Agency who intends to carry on the business of forecasting weather, terrestrial phenomena, tsunami, storm surge, high waves or floods must obtain permission from the Director-General of the agency.
And the permission is scoped, not general
The act adds that permission is granted by specifying the purpose and the scope of the forecasting business. So an operator is not simply licensed to forecast — it is licensed to forecast particular things, for a particular purpose. A permission covering agricultural forecasting is not a permission to issue flood predictions.
The dangerous forecasts are locked down further
There is a category the act calls specified forecasting business, covering forecasts of eruptions, volcanic gas emissions, landslides, tsunami, storm surge or floods. Where a permission includes any of those, the act restricts the purpose: it must be limited to making the forecast available only to those who have received the explanation the statute requires.
A private operator generally cannot take a permission for tsunami or eruption forecasting and simply broadcast the result to the public. The category exists, but its output is channeled to recipients who have been briefed.
Which means that when you see a tsunami warning in Japan, you are seeing the agency's warning. There is no competing private version to weigh it against.
Even measuring is regulated, if you plan to publish
This is the provision that surprised us most, and it explains the quality of the underlying data.
A person who is neither a government body nor a local authority must follow the technical standards set by ministry ordinance when carrying out meteorological observation in either of two cases:
| When the observation is… | Then… |
|---|---|
| 🚨 For results that will be published | Technical standards apply |
| 🚨 For results to be used in preventing disasters | Technical standards apply |
| For research | Excluded (in the parallel rule for public bodies) |
| For education | Excluded (in the parallel rule for public bodies) |
And the instrument has to be declared
Anyone required to observe to the technical standards must notify the Director-General when they install the facility, in the manner ministry ordinance prescribes — and again when they discontinue it. So the national picture includes knowing where the private instruments are, and when one goes away.
The line is drawn around use, not around ownership
Note what is not restricted. Putting a thermometer on your balcony is nobody's business. The obligation attaches when the results are going to be published, or used for disaster prevention. That is a well-chosen boundary: it leaves curiosity alone and captures exactly the measurements that other people will end up relying on.
The definitions put earthquakes in the same statute as rain
The act defines three terms, and the boundaries are drawn in a way that tells you how Japan thinks about natural hazards.
| Term | What the act says it means |
|---|---|
| Weather | Phenomena of the atmosphere — expressly excluding the ionosphere |
| Terrestrial phenomena | Earthquakes and volcanic phenomena, together with phenomena of the ground and underground closely related to weather |
| Hydrological phenomena | Phenomena of inland waters and the ocean closely related to weather, earthquakes or volcanic activity |
One agency, one framework, several kinds of disaster
In many countries the weather service and the seismological service are separate institutions with separate laws. Here, earthquakes and volcanoes are defined into the same statute as rainfall, under one agency. That is the structural reason a single Japanese source can tell you about a typhoon, an earthquake and a volcanic alert in one place — and it is worth knowing alongside our guide to what to do in an earthquake.
And the purpose clause names transport explicitly
The act states that it exists to develop meteorological services soundly and thereby contribute to disaster prevention, the safety of transport, and the growth of industry, along with international cooperation. Transport is named in the purpose of the statute. That is a small thing to notice, and it goes some way to explaining why Japanese railways suspend services on forecast rather than on observation — the operators are acting inside a system where forecasting exists partly for them.
There is a qualification, and it is in the act
The statute contains an entire chapter on certified weather forecasters. We are not going to describe the examination or the qualifying requirements, because we did not retrieve that detail — but the existence of the chapter is itself informative.
It means the person presenting a forecast is working within a framework the legislature built, not simply holding a job at a broadcaster. Combined with the permission system, it produces a chain where the data, the operator and the individual are each regulated separately.
The agency can also commission others
There is a provision running the other way as well: the Director-General may, where necessary, entrust observation or the provision of information to government bodies, local authorities, companies, other organizations or individuals. So the system is not closed — it pulls in outside capacity deliberately, under its own terms.
What this means when a typhoon is coming
A certified forecaster walking through Kikikuru, the real-time risk map the agency publishes during heavy rain. Seven minutes in Japanese, but the map is color-coded and works without language — and knowing it exists is the difference between hearing that a warning was issued and being able to see whether it applies to the street you are on.
The practical consequence is a relief, and it is the opposite of the advice you would give in a lot of places.
The thing to watch instead is the operators
What actually varies during a storm is not the forecast but the response: which railway suspends which line, from what hour, and when it plans to resume. Those decisions are the operators' own, they are announced separately, and they are where your day is decided. Plan around the announcements, not around trying to out-guess the weather — a point that also applies when you are choosing when to visit in the first place.
Why the single-source design is unusual
It is worth naming what is strange here, because it runs against the instinct most travelers bring. In many countries the correct response to a storm is to triangulate — check two or three models, notice where they disagree, and treat the spread as information about uncertainty. That habit is well earned, and in Japan it does almost nothing for you.
The permission system deliberately narrows the field rather than widening it. Whether that is the right trade is a real question — a single authoritative source is only as good as the source — but as a visitor you do not have to resolve it. You need to know which behavior the system rewards, and here it rewards reading one forecast carefully rather than five quickly.
And what we are not going to tell you
We are not describing warning levels, advisory categories or evacuation information tiers in this guide. Those are operational criteria and, in the case of evacuation information, a different statute entirely. Getting a level wrong in a guide is worse than not printing one, and this article is about who may forecast rather than about how the output is graded. The same discipline we applied to the hot springs act applies here: the statute is the source, and where it delegates, we stop.
Deliberately not stated here
The act was our only source. These are gaps, not estimates:
| What we are not saying | Why |
|---|---|
| Warning, advisory and emergency warning criteria | Operational criteria we did not retrieve. No levels are described here. |
| Evacuation information levels | A different statute and a different agency. Not retrieved. |
| What the forecaster examination involves | Detail not retrieved. Only the existence of the qualification is stated. |
| Which apps or services hold permissions | We do not make claims about individual businesses. |
| Typhoon categories or track accuracy | Operational and scientific material, not in the act. |
| Penalty amounts | The penalty articles were not retrieved. |
| Whether earthquakes can be predicted | A scientific question. The act governs the service, not the science. |
(The month these warnings matter most is September: our Japan in September guide has the JMA figure of 1.0 landfalls, the highest of any month, alongside the heat and humidity that have not left yet.)
Japanese weather forecasting FAQ
Can anyone publish a weather forecast in Japan?
Why does that matter to me as a visitor?
Are there extra rules for the dangerous forecasts?
Is taking my own measurements regulated too?
What about observations for research or teaching?
What does the act actually mean by weather?
Is there a qualification for forecasters?
Where should I actually get my forecast as a visitor?
Bottom line (2026) — under the Meteorological Service Act, anyone other than the Japan Meteorological Agency needs the Director-General's permission to run a forecasting business, and that permission is granted for a stated purpose and scope. Forecasts of eruptions, tsunami, storm surge, landslides and floods are a restricted category whose output goes only to briefed recipients. Even observation must meet technical standards where the results will be published or used for disaster prevention, with the instrument notified to the agency. Earthquakes and volcanoes are defined into the same statute as weather. So during a typhoon: read the agency, then watch what the transport operators announce.
(For what else changed this year: our list of Japan travel changes in 2026 notes that from May 29, 2026, the Japan Meteorological Agency puts the alert level number in the name of each warning, with a new Level 4 Urgent Warning one step below the Level 5 Emergency Warning.)
Sources
This guide was written from the Meteorological Service Act (Act No. 165 of 1952), retrieved in Japanese from the Japanese government legal database on September 1, 2026: its purpose of developing meteorological services soundly so as to contribute to disaster prevention, the safety of transport and the growth of industry, together with international cooperation; the definitions of weather as phenomena of the atmosphere excluding the ionosphere, of terrestrial phenomena as earthquakes and volcanic phenomena together with related ground and underground phenomena, and of hydrological phenomena as phenomena of inland waters and the ocean closely related to weather, earthquakes or volcanic activity; the requirement that a person other than the agency obtain the Director-General's permission to carry on the business of forecasting weather, terrestrial phenomena, tsunami, storm surge, high waves or floods; the granting of that permission by specifying the purpose and scope; the treatment of specified forecasting business covering eruptions, volcanic gas emissions, landslides, tsunami, storm surge or floods, whose purpose is limited to making the forecast available only to those who have received the statutory explanation; the requirement that government bodies and local authorities observe to the technical standards set by ministry ordinance, excluding observation for research, for education and as otherwise specified; the requirement that others do the same where the results are for publication or for use in preventing disasters; the duty to notify the Director-General on installing and on discontinuing such a facility; the chapter establishing certified weather forecasters; and the power of the Director-General to entrust observation or information provision to public bodies, companies, other organizations or individuals. Operational criteria are flagged above rather than described. More on how we work: how we research.
Laws change. This reflects the text as it stood on September 1, 2026.
Tokyo to Osaka, Tokyo to Kyushu, Tokyo to Hokkaido — day by day — plus seven places most visitors never reach.
- 12 pages, 80 photographs, every stop linked to its guide
- Every price and opening hour read from the official page
- Re-issued monthly, so it does not go stale in your inbox
Free. One email a month, plus the rare change that matters. Unsubscribe with one click in any email. By subscribing you agree to our privacy policy.
