weather — Enhanced MCP Weather Server

A feature-rich MCP (Model Context Protocol) server that provides comprehensive weather data using the NWS (National Weather Service) public APIs. Includes input validation, error handling, geocoding, and a unique weather comparison feature.

Quick start

1. Install uv (macOS / Linux):

curl -LsSf https://astral.sh/uv/install.sh | sh
# restart your terminal

2. Create project, venv and install deps:

uv init weather
cd weather
uv venv
source .venv/bin/activate
uv add "mcp[cli]" httpx

3. Run the server:

uv run main.py
# or
uv run weather.py

Available Tools

The server provides the following MCP tools:

1. get_alerts(state: str)

Get active weather alerts for a US state.

• Input: Two-letter US state code (e.g., "CA", "NY", "TX")

• Features: Validates state codes, provides detailed alert information

2. get_forecast(latitude: float, longitude: float)

Get detailed weather forecast for a location using coordinates.

• Input: Latitude (-90 to 90) and Longitude (-180 to 180)

• Features: 10-period forecast (5 days), includes humidity and precipitation probability

3. get_forecast_by_city(city_name: str)

Get weather forecast by city name (no coordinates needed!).

• Input: City name (e.g., "San Francisco", "New York", "Chicago")

• Features: Automatic geocoding, works with city names

4. get_current_conditions(latitude: float, longitude: float)

Get real-time current weather conditions.

• Input: Latitude and Longitude

• Features: Temperature, humidity, wind, pressure, visibility, and more

5. compare_weather(location1: str, location2: str)

Compare weather conditions between two locations side-by-side.

• Input: Two locations (city names or "lat,lon" format)

• Features: Side-by-side comparison, temperature difference analysis, supports both city names and coordinates

Features

• ✅ Input Validation: Validates state codes and coordinate ranges

• ✅ Better Error Handling: Specific, helpful error messages

• ✅ Geocoding Support: Search by city name using Open-Meteo geocoding API

• ✅ Current Conditions: Real-time weather observations

• ✅ Enhanced Forecasts: More detailed information including humidity and precipitation

• ✅ Weather Comparison: Unique feature to compare two locations

• ✅ Location Detection: Automatically detects and displays city/state names

Files

• weather.py — Main MCP server implementation with all tools

• main.py — Entry point that imports and runs the server

Notes

• Python 3.11+ required (see pyproject.toml)

• NWS Coverage: The NWS API only covers US territories. International locations will not work.

• Transport: The server uses stdio transport by default

• MCP Clients: Use Claude Desktop, mcp CLI, or another MCP client to connect

• Geocoding: City name search uses Open-Meteo's free geocoding API (no API key required)

Example Usage

Once connected to an MCP client, you can use the tools like:

# Get alerts for California
get_alerts("CA")

# Get forecast by city name
get_forecast_by_city("San Francisco")

# Get current conditions
get_current_conditions(37.7749, -122.4194)

# Compare weather between two cities
compare_weather("New York", "Los Angeles")

License

Apache License 2.0 — see LICENSE. Replace the placeholder year/name in LICENSE if needed.