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Tools

7 tools for working with the NOAA Climate Data Online (CDO) API v2:

noaa_list_datasets

List all available NOAA CDO datasets — approximately 11 in total.

• Returns dataset IDs, names, data coverage fraction, and temporal range
• No required parameters — returns everything by default
• Optionally filter by data type, location, station, or date range
• Common datasets: GHCND (daily, 1763–present), GSOM (monthly), GSOY (annual), NORMAL_DLY/MLY/ANN/HLY (1981–2010 climate normals)
• Start here to orient before calling noaa_fetch_data

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noaa_list_data_categories

List data category groups that organize related measurement types.

• ~41 categories including Temperature, Precipitation, Wind, Pressure, Sunshine, Sky cover, Weather Type
• Optionally filter by dataset, location, station, or date range
• Use before noaa_list_data_types to narrow by measurement domain

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noaa_list_data_types

List specific measurement labels for a dataset or category.

• Hundreds of data types across all datasets
• Filter by dataset (e.g., GHCND) or category (e.g., TEMP) to narrow results
• Common GHCND types: TMAX (max temperature), TMIN (min temperature), PRCP (precipitation), SNOW (snowfall), SNWD (snow depth), AWND (average wind speed)
• Returns ID, name, coverage fraction, and date range per type

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noaa_find_locations

Search geographic locations by category.

• Category types: ST (US states, ~52), CNTY (counties), CITY (cities), CNTRY (countries), ZIP (zip codes), CLIM_REG (NOAA climate regions), CLIM_DIV (climate divisions), hydrological categories
• Use locationCategoryId=ST to list all states in one call; use sortField=name with pagination to browse cities alphabetically
• The CDO API has no name-search parameter — sort by name and page through results to find a specific location
• Returns location IDs (FIPS:37, CITY:US530031, ZIP:98101) used in station search and data queries

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noaa_find_stations

Search weather observation stations.

• Filter by location ID, bounding box (lat/lon), dataset, data type, and date range
• Returns station IDs, names, coordinates, elevation, and data coverage dates
• A station must have data for the dataset and date range you want — pass datasetId and date range to ensure compatibility
• Common station ID formats: GHCND:USC00450974, COOP:010008
• Station IDs returned here feed directly into noaa_fetch_data

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noaa_get_station

Fetch full metadata for a single weather station by ID.

• Returns name, coordinates (decimal degrees), elevation, and full data coverage date range
• Use to verify a station before querying data, or to check its temporal coverage
• Mirrors the noaa://stations/{stationId} resource as a direct lookup

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noaa_fetch_data

Fetch historical observation records from a NOAA CDO dataset.

• Requires datasetId, startDate, and endDate; optionally scoped by station, location, and data type
• Date range limits: sub-daily and daily datasets (GHCND, PRECIP_15, PRECIP_HLY, NORMAL_DLY, NORMAL_HLY) — 1 year max per request; monthly and annual datasets (GSOM, GSOY, NORMAL_MLY, NORMAL_ANN) — 10 years max
• Unit selection: strongly recommended — pass units=metric (SI) or units=standard (Fahrenheit/inches). Without it, GHCND values are raw tenths-of-unit integers (TMAX=256 = 25.6°C, PRCP=12 = 1.2mm); GSOM/GSOY are already scaled
• Climate normals: for any NORMAL_* dataset, use startDate=2010-01-01 and endDate=2010-12-31 — that is the API proxy year regardless of which 30-year period is described
• Returns flat tuples of { date, datatype, station, value, attributes } with pagination metadata

Resources

Features

Built on @cyanheads/mcp-ts-core:

• Declarative tool definitions — single file per tool, framework handles registration and validation
• Unified error handling across all tools
• Pluggable auth (none, jwt, oauth)
• Swappable storage backends: in-memory, filesystem, Supabase, Cloudflare KV/R2/D1
• Structured logging with optional OpenTelemetry tracing
• Runs locally (stdio/HTTP) or on Cloudflare Workers from the same codebase

NOAA CDO-specific:

• Full CDO API v2 coverage — datasets, data categories, data types, locations, stations, and observations
• Client-side date range validation with per-dataset limits enforced before hitting the API
• Unit normalization via the CDO units parameter — avoids raw tenths-of-unit integer confusion
• Retry with exponential backoff for transient API failures

Agent-friendly output:

• Paginated results across all list and search tools — limit, offset, and total count in every response
• Station and dataset IDs flow naturally between tools — find a location, find stations in it, fetch data from those stations
• Structured error contracts with reason codes and recovery hints — agents can branch on data, not string parsing
• Dataset and station resources for injectable, zero-fetch context

Getting started

Self-Hosted / Local

Add the following to your MCP client configuration file.

{
  "mcpServers": {
    "noaa-cdo-mcp-server": {
      "type": "stdio",
      "command": "bunx",
      "args": ["@cyanheads/noaa-cdo-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info",
        "NOAA_CDO_TOKEN": "your-token-here"
      }
    }
  }
}

Or with npx (no Bun required):

{
  "mcpServers": {
    "noaa-cdo-mcp-server": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@cyanheads/noaa-cdo-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info",
        "NOAA_CDO_TOKEN": "your-token-here"
      }
    }
  }
}

Or with Docker:

{
  "mcpServers": {
    "noaa-cdo-mcp-server": {
      "type": "stdio",
      "command": "docker",
      "args": ["run", "-i", "--rm", "-e", "MCP_TRANSPORT_TYPE=stdio", "-e", "NOAA_CDO_TOKEN=your-token-here", "ghcr.io/cyanheads/noaa-cdo-mcp-server:latest"]
    }
  }
}

For Streamable HTTP, set the transport and start the server:

MCP_TRANSPORT_TYPE=http MCP_HTTP_PORT=3010 NOAA_CDO_TOKEN=your-token-here bun run start:http
# Server listens at http://localhost:3010/mcp

Prerequisites

• Bun v1.3.0 or higher (or Node.js ≥24.0.0).
• A free NOAA CDO API token — required for all requests.

Installation

1. Clone the repository:

git clone https://github.com/cyanheads/noaa-cdo-mcp-server.git

2. Navigate into the directory:

cd noaa-cdo-mcp-server

3. Install dependencies:

bun install

Configuration

All configuration is validated at startup via Zod schemas in src/config/server-config.ts. Key environment variables:

Running the server

Local development

• Build and run the production version:

  # One-time build
  bun run rebuild
  
  # Run the built server
  bun run start:http
  # or
  bun run start:stdio
  

• Run checks and tests:

  bun run devcheck  # Lints, formats, type-checks, and more
  bun run test      # Runs the test suite
  

Project structure

Development guide

See CLAUDE.md for development guidelines and architectural rules. The short version:

• Handlers throw, framework catches — no try/catch in tool logic
• Use ctx.log for logging, ctx.state for storage
• Register new tools and resources in the createApp() arrays

Contributing

Issues and pull requests are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

License

This project is licensed under the Apache 2.0 License. See the LICENSE file for details.