Weather MCP Server - Day 10

Overview

Day 10 of the 30-Day RAG Learning Journey focuses on building a Weather MCP Server that integrates with real-time weather APIs. This project combines RAG (Retrieval-Augmented Generation) principles with Location-Based Context Synthesis (LBCS) systems.

Project Structure

day10-weather-mcp/
├── weather_mcp_server.py    # Main MCP server with weather tools
├── test_weather.py          # Test client for API validation
├── requirements.txt         # Python dependencies
├── .env                     # Environment variables (API keys)
├── .env.example            # Template for environment setup
├── README.md               # This file
└── venv/                   # Virtual environment

Features - 5 Weather Tools

1. get_current_weather (location: str)

Returns comprehensive current weather data:

Temperature
Feels Like temperature
Humidity percentage
Weather description
Wind speed
Pressure
Cloud coverage

# Example usage
location = "London"
units = "metric"  # or "imperial", "standard"

2. get_forecast (location: str, days: int)

Returns 5-day weather forecast with daily highs/lows:

Daily high temperatures
Daily low temperatures
Weather conditions
Configurable forecast days (1-5)

# Example usage
location = "Paris"
days = 5

3. get_weather_alerts (location: str)

Returns severe weather warnings and alerts (if any):

Alert event type
Start/end times
Alert descriptions
Severity indicators

# Example usage
location = "New York"

4. compare_locations (location1: str, location2: str)

Returns side-by-side weather comparison:

Temperature comparison
Humidity levels
Wind speeds
Weather conditions
Pressure readings

# Example usage
location1 = "London"
location2 = "New York"

5. get_weather_by_coords (lat: float, lon: float)

Returns weather for specific latitude/longitude:

Temperature at coordinates
Location name (reverse geocoding)
All weather parameters
Pressure, humidity, wind

# Example usage
lat = 51.5074
lon = -0.1278

Tech Stack

Python 3.11: Core programming language
MCP 1.25.0: Model Context Protocol for Claude integration
httpx 0.28.1: Async HTTP client for API calls
OpenWeatherMap API: Real-time weather data provider
python-dotenv: Environment variable management
Async/await patterns: Non-blocking I/O operations

Setup Instructions

1. Prerequisites

Python 3.8+
OpenWeather API key (free tier available)
Virtual environment (recommended)

2. Get API Key

Visit OpenWeather API
Sign up for a free account
Get your API key from the account dashboard
Copy your API key

3. Install Dependencies

# Navigate to directory
cd week2-mcp/day10-weather-mcp

# Create and activate virtual environment
python -m venv venv

# Windows
venv\Scripts\activate

# macOS/Linux
source venv/bin/activate

# Install packages
pip install -r requirements.txt

4. Configure Environment

# Copy template
cp .env.example .env

# Edit .env and add your API key
# WEATHER_API_KEY=your_actual_api_key_here

5. Run Server

python weather_mcp_server.py

6. Test Integration

python test_weather.py

API Response Examples

Current Weather (London)

Current Weather in London, GB:

Description: Partly Cloudy
Temperature: 8.5°C
Feels Like: 6.2°C
Humidity: 72%
Wind Speed: 4.5 m/s
Pressure: 1013 hPa
Cloudiness: 40%

Weather Forecast (5-Day)

5-Day Weather Forecast for London:

Date: 2025-12-28
High: 10.2°C | Low: 5.3°C
Conditions: Rainy
--------------------------------------------------

Date: 2025-12-29
High: 9.1°C | Low: 4.8°C
Conditions: Cloudy
--------------------------------------------------

Weather Comparison

Weather Comparison: London vs Paris
============================================================
London               | Paris
------------------------------------------------------------
Temperature:    8.5°C | 9.2°C
Feels Like:     6.2°C | 7.1°C
Humidity:       72%   | 65%
Conditions:     Cloudy| Clear
Wind Speed:     4.5   | 3.2 m/s

Integration with Claude Desktop

To use this MCP server with Claude Desktop:

Edit your Claude Desktop configuration file:

Windows: %APPDATA%\Claude\claude_desktop_config.json
macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

Add the weather server:

{
  "mcpServers": {
    "weather": {
      "command": "python",
      "args": ["C:\\path\\to\\weather_mcp_server.py"]
    }
  }
}

Restart Claude Desktop

Learning Concepts

RAG & LBCS Integration

This project demonstrates:

Context-Aware Retrieval: Using location data to retrieve relevant weather information
Real-time Data Processing: Async handling of API calls
MCP Protocol: Integrating external tools with LLMs
Error Handling: Graceful degradation when APIs fail
Data Formatting: Structured output for LLM consumption

Key Technologies

asyncio: Asynchronous Python for concurrent requests
httpx: Async HTTP client for API calls
OpenWeather API: Real-time weather data provider
MCP Protocol: Tool integration with Claude
Type Hints: Full Python type annotations

Usage Examples

Ask Claude

"What's the weather like in Tokyo right now?"

Claude uses get_current_weather tool to retrieve current conditions.

"Compare the weather between London, Paris, and New York"

Claude uses compare_locations tool for side-by-side analysis.

"What will the weather be like in Sydney over the next 5 days?"

Claude uses get_forecast tool to get daily predictions.

"Get the weather at coordinates 51.5074, -0.1278"

Claude uses get_weather_by_coords for precise location weather.

"Are there any weather alerts for Los Angeles?"

Claude uses get_weather_alerts to check for severe weather.

Troubleshooting

API Key Not Working

Verify your API key is correct in .env
Check if your OpenWeather account is activated
Ensure you have enough API call quota
Wait 10 minutes after creating account before first use

Connection Errors

Check your internet connection
Verify OpenWeather API is accessible
Check firewall settings
Verify the domain isn't blocked in your region

Import Errors

Ensure virtual environment is activated
Reinstall requirements: pip install -r requirements.txt
Check Python version (3.8+ required)

Tool Not Found Errors

Restart Claude Desktop after adding server config
Verify server config JSON is valid
Check file paths are absolute, not relative

File Descriptions