Mcp Weather Service

What is Mcp Weather Service about?

Delivers real‑time weather conditions and a five‑day forecast for any city by querying the OpenWeatherMap free API. The service is exposed as an MCP server, enabling seamless integration with Claude and other MCP‑compatible tools.

How to use Mcp Weather Service?

Obtain an OpenWeatherMap API key from https://openweathermap.org/api.
Set the environment variable OWM_API_KEY with your key.
Build the binary:
```
go build -o mcp-weather
```

Configure the MCP client (example for Claude Desktop):

{
  "mcpServers": {
    "mcp-openweather": {
      "command": "/path/to/mcp-weather",
      "env": { "OWM_API_KEY": "YOUR_API_KEY" }
    }
  }
}

Invoke the tool with parameters:

{
  "tool": "weather",
  "params": { "city": "Berlin", "units": "c", "lang": "en" }
}

Key Features

Current weather conditions (temperature, humidity, pressure, wind, sunrise/sunset).
5‑day forecast with three‑hour intervals.
Configurable temperature units: Celsius, Fahrenheit, Kelvin.
Multi‑language output for weather descriptions.
Simple MCP JSON interface for easy integration.

Use Cases

Embedding live weather data into AI assistants or chatbots.
Providing weather‑aware suggestions in home automation scenarios.
Supplying meteorological information for travel planning tools.
Enabling developers to prototype weather‑driven applications without handling API calls directly.

FAQ

What if the API key is missing? The server exits with FATAL: OWM_API_KEY environment variable not set.
How are invalid city names handled? Returns an error like current weather error: failed to fetch current weather: city not found.
What happens on network timeouts? Errors such as failed to fetch forecast: context deadline exceeded are returned.
Can I change the default language? Yes, pass the lang parameter (e.g., de, fr, es).
Is there a Docker image? Not provided; the binary can be built and run directly.

A simple MCP service that provides current weather and 5-day forecast using the free OpenWeatherMap API.

Features

Current weather conditions
5-day weather forecast
Configurable units (Celsius/Fahrenheit/Kelvin)
Multi-language support
Simple MCP integration

Prerequisites

Go 1.20+
OpenWeatherMap API key

Installation

Get OpenWeatherMap API key from https://openweathermap.org/api

Clone repository:

git clone https://github.com/mschneider82/mcp-openweather.git
cd mcp-openweather

Build:
```
go build -o mcp-weather
```

Installing via Smithery

To install MCP Weather Service for Claude Desktop automatically via Smithery:

npx -y @smithery/cli install @mschneider82/mcp-openweather --client claude

Configuration

Set required environment variable:

export OWM_API_KEY="your_api_key_here"

Usage


 "mcpServers": {
     "mcp-openweather": {
         "command": "/home/YOURUSER/git/mcp-openweather/mcp-openweather",
         "env": {
             "OWM_API_KEY": "PUT_API_KEY_HERE"
         }
     }
 }

MCP Parameters

 {
     "tool": "weather",
     "params": {
         "city": "Berlin",          // Required
         "units": "c",             // Optional (c|f|k)
         "lang": "en"              // Optional (en|de|fr|...)
     }
 }

Example Response

 Current weather for München:
     Conditions:  Klarer Himmel 
     Now:         17.78 metric
     High:        18.66 metric
     Low:         17.36 metric
     Pressure:    1017
     Humidity:    40
     FeelsLike:   16.66
     Wind Speed:  1.79
     Wind Degree:    61
     Sunrise:     1747107429 Unixtime
     Sunset:      1747161784 Unixtime
 Weather Forecast for München:
 Date & Time: 2025-05-13 12:00:00 +0000 UTC
 Conditions:  Clear Klarer Himmel
 Temp:        17.78 
 High:        18.93 
 Low:         17.78

 Date & Time: 2025-05-13 15:00:00 +0000 UTC
 Conditions:  Clear Klarer Himmel
 Temp:        18.33 
 High:        19.44 
 Low:         18.33

 Date & Time: 2025-05-13 18:00:00 +0000 UTC
 Conditions:  Clear Klarer Himmel
 Temp:        16.32 
 High:        16.32 
 Low:         15.59

 Date & Time: 2025-05-13 21:00:00 +0000 UTC
 Conditions:  Clear Klarer Himmel
 Temp:        9.18 
 High:        9.18 
 Low:         9.18
...

Error Handling

Common error scenarios:

Missing API key: FATAL: OWM_API_KEY environment variable not set

Invalid city: current weather error: failed to fetch current weather: city not found

Network issues: failed to fetch forecast: context deadline exceeded

Development

Contributions welcome! Please follow these steps:

Fork the repository

Create a feature branch

Commit changes

Push to the branch

Create a Pull Request

License

MIT License - see LICENSE for details

Mcp Weather Service