Japan Weekly Weather Forecast API — Free JSON with High/Low Temps and Precipitation Probability

A developer released japan-intel-mcp, a free, keyless MCP server that normalizes the Japan Meteorological Agency's deeply nested, Japanese-documented forecast JSON into a flat structure callable from AI agents or plain Python. The server's japan_weekly_forecast tool returns 7-day high/low temperatures, precipitation probabilities and JMA's A/B/C reliability grades, and it is one of eight read-only tools covering earthquakes, weather warnings, typhoons, EDINET corporate filings and postal lookups. It runs over stdio and is listed on the official MCP registry as io.github.atushi1841/japan-intel-mcp.

If you want Japan's weekly weather forecast as JSON, the data is free and authoritative — it comes from the Japan Meteorological Agency JMA, 気象庁 . The problem is the shape: the JMA publishes it as deeply nested JSON with parallel arrays, one file per prefecture 130000 for Tokyo, 270000 for Osaka… , and the field meanings are only documented in Japanese. This post shows a free MCP server that normalizes it into a flat, predictable structure you can call from an AI agent or plain Python. sources and reports failures in data gaps instead of silently dropping them Calling japan weekly forecast prefecture="東京都" returns this real output, trimmed : { "retrieved at": "2026-10-12T11:54:22+00:00", "sources": "https://www.jma.go.jp/bosai/forecast/data/forecast/130000.json" , "data gaps": , "data": { "prefecture": "東京都", "area code": "130000", "blocks": { "time defines": "2026-10-13T00:00:00+09:00", "..." , "areas": {"area": "東京地方", "weathers": "くもり 時々 晴れ" } }, { "areas": {"area": "東京地方", "pops": "0", "0", "0", "10", "10" } }, { "areas": {"area": "東京", "temps": "17", "25" } }, { "areas": { "area": "東京", "tempsMin": "", "18", "18", "16", "15", "16", "18" , "tempsMax": "", "27", "23", "24", "24", "24", "25" , "reliabilities": "", "", "A", "A", "A", "A", "B" } } } } The last block is the one most people want: 7 days of high/low temperatures plus a reliability grade A/B/C so you can tell how much to trust day 6 and 7. Three things the raw JMA feed makes painful: time defines do not line up 1:1. You have to join them yourself. reliabilities 信頼度 is an A/B/C grade most consumers never notice. The wrapper preserves the block structure so nothing is lost but keeps each series keyed by area , which is what makes it joinable. The server speaks MCP over stdio, so Claude Code, Cursor, or any MCP client can call it directly. { "mcpServers": { "japan-intel-mcp": { "command": "japan-intel-mcp" } } } Then ask your agent something like "what's the forecast for Tokyo this week?" and it will call: japan weekly forecast prefecture="東京都" Weather is one of eight read-only tools in the same server — all free, all keyless: | Tool | What it returns | Source | |---|---|---| | japan earthquakes | Recent quakes: epicenter, magnitude, max intensity, depth | JMA | | japan weather warnings | Active warnings/advisories by prefecture | JMA | | japan weather overview | Narrative weather summary | JMA | | japan weekly forecast | 7-day high/low temps, precipitation %, reliability | JMA | | japan typhoons | Active typhoon tracking | JMA | | japan edinet filings | Statutory corporate disclosures | EDINET | | japan postal lookup | Postal code → address kanji and kana | zipcloud | | japan watch summary | One-call cross-source summary | JMA | pip install -e . japan-intel-mcp stdio mode Source and releases: github.com/atushi1841/japan-intel-mcp https://github.com/atushi1841/japan-intel-mcp Also on the official MCP registry as io.github.atushi1841/japan-intel-mcp . If you are building anything that needs current Japanese conditions — logistics, travel, event planning, or just an agent that should know it is typhoon season — this keeps you off scraped HTML.