We recommend using the following environment. (As of April 2023)
- iOS・iPadOS: iOS・iPadOS latest version, browser is Safari latest version
- Android: latest version of Android, Chrome latest browser
We recommend the latest versions of Edge and Chrome as computer display browsers. (As of April 2023)
On the one hand, rain precipitation indicated by radar differs from the actual rainfall on the ground, because it shows the rainfall intensity in the air before raindrops fall on the ground.
For reference, the image of rainfall display shown in the legend is shown below.
| Hourly Precipitation (mm) | Forecast Terms | Image that people receive | Influence on people | Indoor (in the case of wooden house) | Outdoor | When riding a car |
|---|---|---|---|---|---|---|
| 10 or more - less than 20 | Slightly Heavy rain | Amid driving rain (The rain sounds like “Zah Zah”) | The feet get wet by rain splashing from the ground | Being unable to hear one’s voice well due to rain | There are puddles on the whole ground | |
| 20 or more - less than 30 | Heavy rain | Dousing rain | Getting wet even with an umbrella | Taking approximately half of sleeping people notice the rain | Visibility is poor even with a faster wiper | |
| 30 or more - less than 50 | Intense rain | Rain as if a bucket of water is being emptied | Roads become like a river | When driving at high speed, a water film is formed between the wheel and the road surface and the brake does not work. (hydroplaning phenomenon) | ||
| 50 or more - less than 80 | Very intense rain | Rain in torrents (constant rain with rasping sound like “Goh Goh”) | Umbrella is useless at all | Splashing makes the surroundings whitish and poor visibility | Driving a car is dangerous | |
| 80 or more - | Torrential rain | Feeling of pressure that makes feel stuffy. Feeling of fear. |
Source: Created with reference to Japan Meteorological Agency website
(Prepared in August 2000, partially amended in January 2002, in March 2017 and in September 2017)
- (Note 1)
- When there is a possibility of a disaster due to heavy rain, Heavy Rain Advisory or Flood advisory is announced, when a serious disaster is likely to occur, Heavy Rain Warning or Flood Warning is announced, and if there is a significant risk of a serious disaster, Heavy Rain Emergency Warning.
- (Note 2)
- When short-term heavy rain that occurs only once every few years is observed and analyzed, information of record-breaking heavy rain in short-time is announced. When this information is announced, it means that there is heavy rain in your inhabited area that can lead to landslides, inundation, and flooding of small-and-medium-sized rivers. Information standards vary by region.
displays JR Lines in the map.
displays other companies’ line, subway is not included.
means the place of each station.
The 1 hour rainfall amount, the 3 hours rainfall amount, the 48 hours rainfall amount and the tanked rain amount in soil are used to judge them.
All types of information written below will be shown in this site when announced by JMA.
| Emergency Warning |
Heavy rain、Storm、Snow-storm、Heavy snow、High waves、Storm surge |
| Warning | Heavy rain、Flood、Storm、Snow-storm、Heavy snow、High waves、Storm surge |
| Advisory | Heavy rain、Flood、Gale、Gale and snow、Heavy snow、High waves、Storm surge、Thunderstorm、Snow melting、Dense fog、 Dry air、Avalanche、Low temperature、Frost、Ice accretion、Snow accretion |
In the display without enlarged display, when the resolution of the smartphone is high, there may be a white gap above and below the screen.
In addition, letters may blur in display of area name. This is what happens when machining for display on smartphone.
Consultation and Service Desk
Public Relations and Service Section, General Affairs Division
Bureau of Sewerage, Tokyo Metropolitan of Government
163-8001 Nishi Shinjuku 2-8-1,Shinjuku-ku,Tokyo
Telephone:03-5320-6511(Direct)
Fax:03-5388-1700(Direct)
Reception time:8:30～17:15(Weekdays)
E-Mail form: Click here to send your e-mail.