Alisherkotek/weather-mcp-server

Weather MCP Server

A Model Context Protocol (MCP) server that provides real-time weather information using the OpenWeatherMap API.

Features

• Current Weather: Get real-time weather conditions for any city worldwide
• Weather Forecast: 3-day weather forecast with hourly details
• Weather Alerts: Simulated weather warnings based on current conditions
• Multi-location Support: Query weather for any city with optional country code
• Error Handling: Graceful handling of invalid locations and API failures

Prerequisites

• .NET 8.0 or later
• OpenWeatherMap API key (free tier available)

Setup Instructions

1. Get an OpenWeatherMap API Key

1. Visit OpenWeatherMap
2. Sign up for a free account
3. Generate an API key from your account dashboard

2. Configure Environment Variable

Windows (PowerShell):

$env:OPENWEATHERMAP_API_KEY = "api_key"

Windows (Command Prompt):

set OPENWEATHERMAP_API_KEY=api_key

Linux/macOS:

export OPENWEATHERMAP_API_KEY="api_key"

3. Build and Run

cd WeatherMcpServer
dotnet restore
dotnet run

Available Tools

get_current_weather

Gets current weather conditions for a specified city.

Parameters:

• city (required): The cityy name to get weather for
• countryCode (optional): Country code (e.g., 'US', 'UK')

Example:

{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"get_current_weather","arguments":{"city":"London"}}}

get_weather_forecast

Gets weather forecast for the next 3 days.

Parameters:

• city (required): The cityy name to get forecast for
• countryCode (optional): Country code (e.g., 'US', 'UK')

Example:

{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"get_weather_forecast","arguments":{"city":"Tokyo"}}}

get_weather_alerts

Gets weather alerts and warnings for a location (simulated based on conditions).

Parameters:

• city (required): The city name to check for alerts
• countryCode (optional): Country code (e.g., 'US', 'UK')

Example:

{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"get_weather_alerts","arguments":{"city":"Miami","countryCode":"US"}}}

Testing the Server

1. Initialize the server:

{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"1.0.0","capabilities":{},"clientInfo":{"name":"test-client","version":"1.0.0"}}}

2. List available tools:

{"jsonrpc":"2.0","id":2,"method":"tools/list"}

3. Call a tool:

{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"get_current_weather","arguments":{"city":"London"}}}

Local Development Configuration

To configure the server for local development in your IDE:

VS Code: Create .vscode/mcp.json:

{
  "servers": {
    "WeatherMcpServer": {
      "type": "stdio",
      "command": "dotnet",
      "args": [
        "run",
        "--project",
        "C:/path/to/WeatherMcpServer"
      ]
    }
  }
}

Visual Studio: Create .mcp.json in solution directory:

{
  "servers": {
    "WeatherMcpServer": {
      "type": "stdio",
      "command": "dotnet",
      "args": [
        "run",
        "--project",
        "WeatherMcpServer"
      ]
    }
  }
}

Project Structure

WeatherMcpServer/
├── Program.cs              # Entry point
├── Services/
│   └── WeatherService.cs   # OpenWeatherMap API integration
├── Tools/
│   └── WeatherTools.cs     # MCP tool implementations
├── WeatherMcpServer.csproj # Project configuration
├── .mcp/
│   └── server.json         # MCP server metadata
└── README.md              # This file

Implementation Details

• Uses metric units (Celsius, m/s) by default
• Weather alerts are simulated based on current conditions
• Forecast provides 3-day outlook with 3-hour intervals
• All responses include proper error handling for invalid inputs

Troubleshooting

401 Unauthorized Error:

• Verify your API key is correctly set as an environment variable
• Ensure you've restarted the server after setting the API key
• Check that your API key is active on OpenWeatherMap

City Not Found:

• Verify the city name spelling
• Try adding a country code for more specific results
• Use major city names for best results

Example Responses

Current Weather:

Current weather in London:
Temperature: 15.2°C (feels like 14.8°C)
Condition: light rain
Humidity: 82%
Wind: 4.1 m/s
Visibility: 10 km

Weather Forecast:

Weather forecast for London, GB:

Monday, January 20
  Temperature: 8.5°C - 12.3°C
  Condition: light rain
  09:00 - 9.2°C, light rain
  12:00 - 11.8°C, overcast clouds
  15:00 - 12.1°C, light rain

Weather Alerts:

Weather alerts for Phoenix:
HEAT WARNING: Extreme temperatures expected. Stay hydrated and avoid prolonged sun exposure.