MCP Weather Server POC

A proof of concept MCP (Model Context Protocol) server that integrates with external REST APIs to provide weather information.

Features

• hello: Simple greeting tool

• get_weather: Get weather by latitude and longitude coordinates

• get_weather_by_location: Get weather by city/location name

Related MCP server: weather-mcp-server

Weather Data

This POC uses the Open-Meteo API (free, no API key required):

• Forecast data: https://api.open-meteo.com/v1/forecast

• Geocoding: https://geocoding-api.open-meteo.com/v1/search

Setup

1. Create Virtual Environment (if not already created)

python -m venv venv

2. Activate Virtual Environment

On Windows (PowerShell):

(Set-ExecutionPolicy -Scope Process -ExecutionPolicy RemoteSigned) ; (& .\venv\Scripts\Activate.ps1)

On Windows (CMD):

venv\Scripts\activate

On macOS/Linux:

source venv/bin/activate

3. Install Dependencies

pip install -r requirements.txt

Running the Server

python server.py

The server will start and be ready to receive requests from MCP clients.

Usage Examples

In an MCP Client

Get weather by location name

Tool: get_weather_by_location
Parameters:
  - location: "London"

Response:

Current Weather in London, United Kingdom:
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Temperature: 15.2°C
Humidity: 72%
Condition: Partly cloudy
Wind Speed: 12.5 km/h
Time: 2024-06-25T14:30

Get weather by coordinates

Tool: get_weather
Parameters:
  - latitude: 51.5074
  - longitude: -0.1278

Simple greeting

Tool: hello
Parameters:
  - name: "World"

Testing with curl (if exposed via HTTP)

curl http://localhost:8000/tools/call \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{"tool": "get_weather_by_location", "params": {"location": "Tokyo"}}'

Supported Weather Codes

The server uses WMO weather codes and interprets them as:

• 0: Clear sky

• 1-3: Various cloud coverage

• 45-48: Fog conditions

• 51-82: Various precipitation types

• 95-99: Thunderstorm conditions

Architecture

┌──────────────────┐
│   MCP Client     │
└────────┬─────────┘
         │
         │ (MCP Protocol)
         │
┌────────▼─────────────────┐
│   MCP Server (FastMCP)   │
│  ┌──────────────────────┐│
│  │ Tools:               ││
│  │ - hello              ││
│  │ - get_weather        ││
│  │ - get_weather_...    ││
│  └──────────────────────┘│
└────────┬─────────────────┘
         │
         │ (REST API)
         │
┌────────▼──────────────────┐
│   Open-Meteo API          │
│   - Weather Data          │
│   - Geocoding             │
└───────────────────────────┘

Error Handling

The server includes error handling for:

• Network timeouts

• Connection errors

• Invalid locations

• HTTP errors

• Malformed responses

License

MIT License

Future Enhancements

• Add historical weather data

• Add weather forecasts (multi-day)

• Add severe weather alerts

• Add precipitation probability

• Support multiple weather providers

• Add caching for repeated requests

• Add UV index information