Yr No Weather Mcp

yr-no-weather-mcp

An MCP server providing Norwegian weather data from MET.no (yr.no) with geocoding via Norkart/Geonorge. Written in Go.

Give any MCP-capable AI assistant access to real-time Norwegian weather — useful for home automation agents, daily briefing bots, trip planning assistants, or any scenario where an LLM needs to reason about current or upcoming weather in Norway.

Features

• Three weather tools — daily forecast, hourly forecast, and precipitation details
• Norwegian place name geocoding — just say "Bergen" or "Tromsø"
• Coordinate support — pass lat,lon directly
• Caching — respects MET.no Expires headers; geocoding cached for 24h
• No API keys required — both MET.no and Geonorge are free public APIs
• Scale-to-zero ready — lightweight Go binary, works great on Knative

Tools

| Tool | Description | | ------------------- | --------------------------------------------------- | | get_forecast | Daily weather summary for next 7 days | | get_hourly | Hourly forecast (temperature, wind, precip, clouds) | | get_precipitation | Precipitation details for today/tomorrow/week |

All tools accept a location parameter — either a Norwegian place name (e.g. "Bergen", "Tromsø") or coordinates as lat,lon (e.g. "60.39,5.32").

Quick Start

Run locally

go build -o yr .
./yr

# Test MCP protocol
mise run test:mcp

The server starts on port 8080 by default:

• Health check: http://localhost:8080/health
• MCP SSE endpoint: http://localhost:8080/sse

Docker

# Build
docker build -t yr-no-weather-mcp .

# Run
docker run -p 8080:8080 yr-no-weather-mcp

Environment Variables

| Variable | Default | Description | | ---------- | ----------------------- | ----------------------- | | BASE_URL | http://localhost:8080 | Public base URL for SSE |

Usage with mcporter

mcporter can connect to this server as a remote MCP tool:

# Call the forecast tool directly
mcporter call yr.get_forecast location=Bergen

# Get hourly weather for Oslo
mcporter call yr.get_hourly location=Oslo hours=6

# Check precipitation for the week
mcporter call yr.get_precipitation location=Tromsø period=week

Configure mcporter to point at your running instance (locally or deployed) and any MCP-compatible agent can use the weather tools.

Architecture

MCP Client (mcporter, Claude, etc.)
    │ HTTP/SSE (JSON-RPC)
    ▼
yr-no-weather-mcp (:8080)
    │
    ├── api.met.no (weather data)
    └── ws.geonorge.no (geocoding)

• Implements the Model Context Protocol over HTTP+SSE
• Uses mcp-go SDK
• User-Agent header set per MET.no Terms of Service
• Stateless — all caching is in-memory

Testing

go test -v ./...

Data Sources

• Weather: MET.no Locationforecast 2.0 — free, no API key required
• Geocoding: Geonorge Stedsnavn API — Norwegian place name search, free

Both APIs are provided by Norwegian government agencies and are free for public use.

License

MIT

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Starefossen
• Source: Starefossen/yr-no-weather-mcp
• License: MIT

Install and usage instructions live in the source repository linked above.