Japan Weather Forecast (JMA)
Pricing
Pay per usage
Japan Weather Forecast (JMA)
Get official Japan Meteorological Agency forecasts for any prefecture as clean, English-keyed JSON: daily weather, rain probability, min/max temperature, and the 7-day outlook.
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Pay per usage
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Japan Open Data
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Official weather forecasts for every region of Japan, from the Japan Meteorological Agency (JMA), returned as clean JSON with English keys.
JMA publishes its forecasts only in Japanese, in a nested format that changes by region. This Actor flattens it into one row per area per day, so you can drop it straight into a spreadsheet, a travel app, a logistics plan or an AI agent.
What you get
- Daily forecast (today and the next 1–2 days) for each sub-area of a prefecture
- weather code and a simple
condition(sunny/cloudy/rain/snow) - the original Japanese forecast text, wind and waves
- rain probability for each 6-hour block, plus the day's maximum
- min / max temperature for each observation city
- weather code and a simple
- 7-day outlook (optional): condition, rain probability, JMA's reliability grade (A/B/C), min / max temperature
- When JMA issued the forecast (
reportedAt) and the data source on every row
Input
| Field | Example | Notes |
|---|---|---|
prefectures | ["Tokyo", "Osaka", "京都府", "016000"] | English name, Japanese name or JMA office code. Leave empty for all of Japan. |
includeWeekly | true | Add the 7-day outlook. |
Unknown names are skipped with a warning, so one typo does not stop the run.
Output example
{"type": "daily","office": "Tokyo","areaJa": "東京地方","date": "2026-10-22","weatherCode": "101","condition": "sunny","weatherJa": "晴れ 朝晩 くもり","rainChanceMaxPercent": 10,"cityTemperatures": [{ "cityJa": "東京", "tempMinC": 19, "tempMaxC": 25 }],"reportedAt": "2026-10-21T05:00:00+09:00","source": "Japan Meteorological Agency (https://www.jma.go.jp/)"}
Notes
- JMA updates forecasts at about 05:00, 11:00 and 17:00 JST. Running more often returns the same data.
- On the day of issue, today's minimum temperature has already passed, so
tempMinCis empty for today. - Tokachi is published inside Kushiro/Nemuro, and Amami inside Kagoshima; asking for them returns those files.
- The whole of Japan (56 forecast files) takes about 30 seconds.
Data source and terms
Source: Japan Meteorological Agency website (気象庁ホームページ). JMA content can be reused, including commercially, when the source is credited (JMA website terms of use, compatible with CC BY 4.0). Every row includes the source field so you can credit it. This Actor is not affiliated with JMA.