getWeatherForecast

Retrieve precise weather forecasts for Swiss locations by specifying a location ID and optional date. Access detailed hourly and daily data with the LandiWetter MCP Server API.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`date`	No	Optional: The date for the forecast (yyyy-MM-dd). Defaults to today
`locationId`	Yes	The location ID (e.g., G2661552)

Implementation Reference

src/index.js:83-151 (handler)

Primary execution logic for the getWeatherForecast tool: validates date, fetches data via helper, formats detailed forecast output, handles errors.

async ({ locationId, date }) => {
  try {
    // Use provided date or default to today
    const forecastDate = date ? new Date(date) : new Date();
    
    // Validate date
    if (isNaN(forecastDate.getTime())) {
      return {
        content: [{ type: "text", text: "Invalid date format. Please use yyyy-MM-dd." }],
        isError: true
      };
    }
    
    const forecast = await getWeatherForecast(locationId, forecastDate);
    
    // Handle error if forecast data is incomplete
    if (!forecast || !forecast.datum) {
      console.error('Invalid forecast data:', forecast);
      return {
        content: [{ type: "text", text: "Received invalid forecast data from API." }],
        isError: true
      };
    }
    
    // Format the response nicely using the actual structure
    let formattedForecast = `Weather Forecast for date ${forecast.datum}:\n\n`;
    
    // Add general weather overview for the whole day
    if (forecast.ganzertag) {
      const dayData = forecast.ganzertag;
      formattedForecast += `### Daily Overview\n`;
      formattedForecast += `Temperature: ${dayData.uebersicht.mintemp} to ${dayData.uebersicht.maxtemp}\n`;
      formattedForecast += `Precipitation: ${dayData.niederschlag.menge} (Probability: ${dayData.niederschlag.wahrscheinlichkeit})\n`;
      formattedForecast += `Cloud coverage: ${dayData.niederschlag.wolken}\n`;
      formattedForecast += `Wind: ${dayData.wind.geschwindigkeit} from ${dayData.wind.richtung}\n`;
      formattedForecast += `Sunshine duration: ${dayData.sonne.dauer}\n\n`;
    }
    
    // Add time sections for detailed forecast
    if (forecast.abschnitte && forecast.abschnitte.length > 0) {
      formattedForecast += `### Hourly Forecast\n`;
      
      forecast.abschnitte.forEach(section => {
        formattedForecast += `\n${section.zeitvon} - ${section.zeitbis}:\n`;
        formattedForecast += `Temperature: ${section.uebersicht.mintemp} to ${section.uebersicht.maxtemp}\n`;
        formattedForecast += `Precipitation: ${section.niederschlag.menge} (Probability: ${section.niederschlag.wahrscheinlichkeit})\n`;
        formattedForecast += `Wind: ${section.wind.geschwindigkeit} from ${section.wind.richtung}\n`;
      });
    }
    
    // Add general weather situation and outlook if available
    if (forecast.allgemeineLage) {
      formattedForecast += `\n### General Weather Situation\n${forecast.allgemeineLage}\n`;
    }
    
    if (forecast.aussichten) {
      formattedForecast += `\n### Outlook\n${forecast.aussichten}\n`;
    }
    
    return {
      content: [{ type: "text", text: formattedForecast }]
    };
  } catch (error) {
    return {
      content: [{ type: "text", text: `Error: ${error.message}` }],
      isError: true
    };
  }
}

src/index.js:33-45 (helper)

Core helper function that constructs the API URL using locationId and formatted date, fetches forecast data from LandiWetter API via axios, returns raw data or throws error.

async function getWeatherForecast(locationId, date) {
  try {
    const formattedDate = formatDate(date);
    const url = `https://www.landi.ch/weather/api/lokalprognose/de/${formattedDate}/${locationId}`;
    console.error('Weather API URL:', url);
    const response = await axios.get(url);
    console.error('Weather API Response:', JSON.stringify(response.data, null, 2));
    return response.data;
  } catch (error) {
    console.error("Error fetching weather forecast:", error.message);
    throw new Error(`Failed to fetch weather forecast: ${error.message}`);
  }
}

src/index.js:79-82 (schema)

Input schema using Zod for tool parameters: required locationId (string) and optional date (string).

{ 
  locationId: z.string().describe("The location ID (e.g., G2661552)"),
  date: z.string().optional().describe("Optional: The date for the forecast (yyyy-MM-dd). Defaults to today")
},

src/index.js:77-152 (registration)

Tool registration via server.tool() specifying name, input schema, and handler function.

server.tool(
  "getWeatherForecast",
  { 
    locationId: z.string().describe("The location ID (e.g., G2661552)"),
    date: z.string().optional().describe("Optional: The date for the forecast (yyyy-MM-dd). Defaults to today")
  },
  async ({ locationId, date }) => {
    try {
      // Use provided date or default to today
      const forecastDate = date ? new Date(date) : new Date();
      
      // Validate date
      if (isNaN(forecastDate.getTime())) {
        return {
          content: [{ type: "text", text: "Invalid date format. Please use yyyy-MM-dd." }],
          isError: true
        };
      }
      
      const forecast = await getWeatherForecast(locationId, forecastDate);
      
      // Handle error if forecast data is incomplete
      if (!forecast || !forecast.datum) {
        console.error('Invalid forecast data:', forecast);
        return {
          content: [{ type: "text", text: "Received invalid forecast data from API." }],
          isError: true
        };
      }
      
      // Format the response nicely using the actual structure
      let formattedForecast = `Weather Forecast for date ${forecast.datum}:\n\n`;
      
      // Add general weather overview for the whole day
      if (forecast.ganzertag) {
        const dayData = forecast.ganzertag;
        formattedForecast += `### Daily Overview\n`;
        formattedForecast += `Temperature: ${dayData.uebersicht.mintemp} to ${dayData.uebersicht.maxtemp}\n`;
        formattedForecast += `Precipitation: ${dayData.niederschlag.menge} (Probability: ${dayData.niederschlag.wahrscheinlichkeit})\n`;
        formattedForecast += `Cloud coverage: ${dayData.niederschlag.wolken}\n`;
        formattedForecast += `Wind: ${dayData.wind.geschwindigkeit} from ${dayData.wind.richtung}\n`;
        formattedForecast += `Sunshine duration: ${dayData.sonne.dauer}\n\n`;
      }
      
      // Add time sections for detailed forecast
      if (forecast.abschnitte && forecast.abschnitte.length > 0) {
        formattedForecast += `### Hourly Forecast\n`;
        
        forecast.abschnitte.forEach(section => {
          formattedForecast += `\n${section.zeitvon} - ${section.zeitbis}:\n`;
          formattedForecast += `Temperature: ${section.uebersicht.mintemp} to ${section.uebersicht.maxtemp}\n`;
          formattedForecast += `Precipitation: ${section.niederschlag.menge} (Probability: ${section.niederschlag.wahrscheinlichkeit})\n`;
          formattedForecast += `Wind: ${section.wind.geschwindigkeit} from ${section.wind.richtung}\n`;
        });
      }
      
      // Add general weather situation and outlook if available
      if (forecast.allgemeineLage) {
        formattedForecast += `\n### General Weather Situation\n${forecast.allgemeineLage}\n`;
      }
      
      if (forecast.aussichten) {
        formattedForecast += `\n### Outlook\n${forecast.aussichten}\n`;
      }
      
      return {
        content: [{ type: "text", text: formattedForecast }]
      };
    } catch (error) {
      return {
        content: [{ type: "text", text: `Error: ${error.message}` }],
        isError: true
      };
    }
  }
);

src/index.js:16-18 (helper)
Utility helper to format a Date object to yyyy-MM-dd string used in API calls.
```
function formatDate(date) {
  return date.toISOString().split('T')[0];
}
```

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