get-forecast
Retrieve weather forecasts for US locations by providing latitude and longitude coordinates.
Instructions
Get weather forecast for a location
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| latitude | Yes | Latitude of the location | |
| longitude | Yes | Longitude of the location |
Implementation Reference
- src/index.ts:150-223 (handler)The inline async handler function for the 'get-forecast' tool. It takes latitude and longitude, fetches grid points and forecast data from the National Weather Service API, formats the forecast periods, and returns them as text content.
async ({ latitude, longitude }) => { // Get grid point data const pointsData = await makeNWSRequest<PointsResponse>( `/points/${latitude.toFixed(4)},${longitude.toFixed(4)}` ); if (!pointsData) { return { content: [ { type: "text", text: `Failed to retrieve grid point data for coordinates: ${latitude}, ${longitude}. This location may not be supported by the NWS API (only US locations are supported).`, }, ], }; } const forecastUrl = pointsData.properties?.forecast; if (!forecastUrl) { return { content: [ { type: "text", text: "Failed to get forecast URL from grid point data", }, ], }; } // Get forecast data - using full URL since the forecast URL is absolute const forecastData = await makeNWSRequest<ForecastResponse>(forecastUrl); if (!forecastData) { return { content: [ { type: "text", text: "Failed to retrieve forecast data", }, ], }; } const periods = forecastData.properties?.periods || []; if (periods.length === 0) { return { content: [ { type: "text", text: "No forecast periods available", }, ], }; } // Format forecast periods const formattedForecast = periods.map((period: ForecastPeriod) => [ `${period.name || "Unknown"}:`, `Temperature: ${period.temperature || "Unknown"}°${period.temperatureUnit || "F"}`, `Wind: ${period.windSpeed || "Unknown"} ${period.windDirection || ""}`, `${period.shortForecast || "No forecast available"}`, "---", ].join("\n"), ); return { content: [ { type: "text", text: formattedForecast.join("\n"), }, ], }; }, - src/index.ts:146-149 (schema)Zod input schema for the 'get-forecast' tool, validating latitude and longitude parameters.
{ latitude: z.number().min(-90).max(90).describe("Latitude of the location"), longitude: z.number().min(-180).max(180).describe("Longitude of the location"), }, - src/index.ts:143-224 (registration)Registration of the 'get-forecast' tool on the MCP server, specifying name, description, input schema, and handler.
server.tool( "get-forecast", "Get weather forecast for a location", { latitude: z.number().min(-90).max(90).describe("Latitude of the location"), longitude: z.number().min(-180).max(180).describe("Longitude of the location"), }, async ({ latitude, longitude }) => { // Get grid point data const pointsData = await makeNWSRequest<PointsResponse>( `/points/${latitude.toFixed(4)},${longitude.toFixed(4)}` ); if (!pointsData) { return { content: [ { type: "text", text: `Failed to retrieve grid point data for coordinates: ${latitude}, ${longitude}. This location may not be supported by the NWS API (only US locations are supported).`, }, ], }; } const forecastUrl = pointsData.properties?.forecast; if (!forecastUrl) { return { content: [ { type: "text", text: "Failed to get forecast URL from grid point data", }, ], }; } // Get forecast data - using full URL since the forecast URL is absolute const forecastData = await makeNWSRequest<ForecastResponse>(forecastUrl); if (!forecastData) { return { content: [ { type: "text", text: "Failed to retrieve forecast data", }, ], }; } const periods = forecastData.properties?.periods || []; if (periods.length === 0) { return { content: [ { type: "text", text: "No forecast periods available", }, ], }; } // Format forecast periods const formattedForecast = periods.map((period: ForecastPeriod) => [ `${period.name || "Unknown"}:`, `Temperature: ${period.temperature || "Unknown"}°${period.temperatureUnit || "F"}`, `Wind: ${period.windSpeed || "Unknown"} ${period.windDirection || ""}`, `${period.shortForecast || "No forecast available"}`, "---", ].join("\n"), ); return { content: [ { type: "text", text: formattedForecast.join("\n"), }, ], }; }, ); - src/index.ts:29-45 (helper)Helper function used by the get-forecast handler to make API requests to the NWS weather service with axios and error handling.
async function makeNWSRequest<T>(url: string): Promise<T | null> { try { const response = await api.get<T>(url); return response.data; } catch (error) { if (axios.isAxiosError(error)) { console.error("Error making NWS request:", error.message); if (error.response) { console.error("Response status:", error.response.status); console.error("Response data:", error.response.data); } } else { console.error("Unexpected error:", error); } return null; } } - src/index.ts:83-93 (schema)TypeScript interfaces defining the structure of NWS API responses used in the get-forecast handler (PointsResponse and ForecastResponse). Also nearby ForecastPeriod (70-77).
interface PointsResponse { properties: { forecast?: string; }; } interface ForecastResponse { properties: { periods: ForecastPeriod[]; }; } - src/index.ts:70-77 (schema)TypeScript interface for ForecastPeriod used in parsing forecast data.
interface ForecastPeriod { name?: string; temperature?: number; temperatureUnit?: string; windSpeed?: string; windDirection?: string; shortForecast?: string; }