--- name: free-weather-data description: "Get current weather, forecasts, and historical data using free Open-Meteo and wttr.in APIs. Use when: (1) Fetching weather conditions, (2) Weather alerts and monitoring, (3) Forecast data for planning, or (4) Climate analysis." --- # Free Weather Data API — Open-Meteo & wttr.in Get current weather, forecasts, and historical weather data using free APIs. No API keys required. Privacy-respecting alternative to paid weather APIs ($5-100/month). ## Why This Replaces Paid Weather APIs **💰 Cost savings:** - ✅ **100% free** — no API keys, no rate limits - ✅ **Comprehensive data** — current, forecast, historical weather - ✅ **Open source** — Open-Meteo is fully open-source - ✅ **Privacy-first** — no tracking or data collection **Perfect for AI agents that need:** - Weather conditions for location-based decisions - Forecast data for planning and scheduling - Historical weather data for analysis - Weather alerts and monitoring ## Quick comparison | Service | Cost | Rate limit | API key required | Privacy | |---------|------|------------|------------------|---------| | OpenWeatherMap | $0-180/month | 60 calls/min free | ✅ Yes | ❌ Tracked | | WeatherAPI | $0-70/month | 1M calls/month free | ✅ Yes | ❌ Tracked | | **Open-Meteo** | **Free** | **10k req/day** | **❌ No** | **✅ Private** | | **wttr.in** | **Free** | **Unlimited** | **❌ No** | **✅ Private** | ## Skills ### get_current_weather_open_meteo Get current weather using Open-Meteo (most accurate and comprehensive). ```bash # Current weather by coordinates LAT=40.7128 LON=-74.0060 curl -s "https://api.open-meteo.com/v1/forecast?latitude=${LAT}&longitude=${LON}¤t=temperature_2m,relative_humidity_2m,apparent_temperature,precipitation,weather_code,wind_speed_10m&temperature_unit=fahrenheit" \ | jq '{ temperature: .current.temperature_2m, feels_like: .current.apparent_temperature, humidity: .current.relative_humidity_2m, wind_speed: .current.wind_speed_10m, precipitation: .current.precipitation, weather_code: .current.weather_code }' # With timezone curl -s "https://api.open-meteo.com/v1/forecast?latitude=${LAT}&longitude=${LON}¤t=temperature_2m,weather_code&timezone=America/New_York" \ | jq '{temperature: .current.temperature_2m, time: .current.time}' ``` **Node.js:** ```javascript async function getCurrentWeather(lat, lon, unit = 'fahrenheit') { const params = new URLSearchParams({ latitude: lat.toString(), longitude: lon.toString(), current: 'temperature_2m,relative_humidity_2m,apparent_temperature,precipitation,weather_code,wind_speed_10m,wind_direction_10m', temperature_unit: unit }); const res = await fetch(`https://api.open-meteo.com/v1/forecast?${params}`); if (!res.ok) { throw new Error(`Weather API failed: ${res.status}`); } const data = await res.json(); return { temperature: data.current.temperature_2m, feelsLike: data.current.apparent_temperature, humidity: data.current.relative_humidity_2m, windSpeed: data.current.wind_speed_10m, windDirection: data.current.wind_direction_10m, precipitation: data.current.precipitation, weatherCode: data.current.weather_code, time: data.current.time, unit: data.current_units.temperature_2m }; } // Usage // getCurrentWeather(40.7128, -74.0060, 'fahrenheit') // .then(weather => { // console.log(`Temperature: ${weather.temperature}°${weather.unit}`); // console.log(`Feels like: ${weather.feelsLike}°${weather.unit}`); // console.log(`Humidity: ${weather.humidity}%`); // console.log(`Wind: ${weather.windSpeed} mph`); // }); ``` ### get_weather_forecast Get weather forecast for the next 7-16 days. ```bash # 7-day forecast LAT=37.7749 LON=-122.4194 curl -s "https://api.open-meteo.com/v1/forecast?latitude=${LAT}&longitude=${LON}&daily=temperature_2m_max,temperature_2m_min,precipitation_sum,weather_code&temperature_unit=fahrenheit&timezone=America/Los_Angeles" \ | jq '{ dates: .daily.time, max_temp: .daily.temperature_2m_max, min_temp: .daily.temperature_2m_min, precipitation: .daily.precipitation_sum }' # Hourly forecast for next 24 hours curl -s "https://api.open-meteo.com/v1/forecast?latitude=${LAT}&longitude=${LON}&hourly=temperature_2m,precipitation,weather_code&forecast_days=1" \ | jq '{hourly: [.hourly.time, .hourly.temperature_2m, .hourly.precipitation] | transpose | map({time: .[0], temp: .[1], precip: .[2]})}' ``` **Node.js:** ```javascript async function getWeatherForecast(lat, lon, days = 7, unit = 'fahrenheit') { const params = new URLSearchParams({ latitude: lat.toString(), longitude: lon.toString(), daily: 'temperature_2m_max,temperature_2m_min,precipitation_sum,precipitation_probability_max,weather_code,wind_speed_10m_max', temperature_unit: unit, forecast_days: days.toString() }); const res = await fetch(`https://api.open-meteo.com/v1/forecast?${params}`); if (!res.ok) { throw new Error(`Forecast API failed: ${res.status}`); } const data = await res.json(); return data.daily.time.map((date, i) => ({ date, maxTemp: data.daily.temperature_2m_max[i], minTemp: data.daily.temperature_2m_min[i], precipitation: data.daily.precipitation_sum[i], precipitationProbability: data.daily.precipitation_probability_max[i], maxWindSpeed: data.daily.wind_speed_10m_max[i], weatherCode: data.daily.weather_code[i] })); } // Usage // getWeatherForecast(37.7749, -122.4194, 7, 'fahrenheit') // .then(forecast => { // forecast.forEach(day => { // console.log(`${day.date}: ${day.minTemp}°-${day.maxTemp}°, ${day.precipitationProbability}% rain`); // }); // }); ``` ### get_weather_wttr_simple Get simple weather using wttr.in (human-readable, very fast). ```bash # Get weather by city name (plain text) curl -s "https://wttr.in/London?format=3" # Output: London: ☀️ +22°C # Get detailed weather report curl -s "https://wttr.in/Paris" # JSON format curl -s "https://wttr.in/Tokyo?format=j1" | jq '.current_condition[0] | { temp_f: .temp_F, humidity: .humidity, description: .weatherDesc[0].value, wind_mph: .windspeedMiles }' # Custom format (temperature and condition) curl -s "https://wttr.in/NewYork?format=%C+%t" # Output: Clear +75°F # Get weather by coordinates curl -s "https://wttr.in/40.7128,-74.0060?format=%l:+%C+%t" ``` **Node.js:** ```javascript async function getWeatherWttr(location) { // location can be city name or "lat,lon" const res = await fetch(`https://wttr.in/${encodeURIComponent(location)}?format=j1`); if (!res.ok) { throw new Error(`Weather API failed: ${res.status}`); } const data = await res.json(); const current = data.current_condition[0]; return { location: data.nearest_area[0]?.areaName[0]?.value || location, tempF: parseInt(current.temp_F), tempC: parseInt(current.temp_C), feelsLikeF: parseInt(current.FeelsLikeF), feelsLikeC: parseInt(current.FeelsLikeC), humidity: parseInt(current.humidity), description: current.weatherDesc[0].value, windMph: parseInt(current.windspeedMiles), windKmh: parseInt(current.windspeedKmph), precipMM: parseFloat(current.precipMM), uvIndex: parseInt(current.uvIndex) }; } // Usage // getWeatherWttr('San Francisco') // .then(weather => { // console.log(`${weather.location}: ${weather.description}`); // console.log(`Temperature: ${weather.tempF}°F (feels like ${weather.feelsLikeF}°F)`); // console.log(`Humidity: ${weather.humidity}%`); // }); ``` ### get_historical_weather Get historical weather data (past dates). ```bash # Historical weather for specific date range LAT=51.5074 LON=-0.1278 START_DATE="2024-01-01" END_DATE="2024-01-31" curl -s "https://archive-api.open-meteo.com/v1/archive?latitude=${LAT}&longitude=${LON}&start_date=${START_DATE}&end_date=${END_DATE}&daily=temperature_2m_max,temperature_2m_min,precipitation_sum" \ | jq '{ dates: .daily.time, max_temps: .daily.temperature_2m_max, min_temps: .daily.temperature_2m_min, precipitation: .daily.precipitation_sum }' # Historical average for a month curl -s "https://archive-api.open-meteo.com/v1/archive?latitude=${LAT}&longitude=${LON}&start_date=2024-01-01&end_date=2024-01-31&daily=temperature_2m_mean" \ | jq '[.daily.temperature_2m_mean[]] | add / length' ``` **Node.js:** ```javascript async function getHistoricalWeather(lat, lon, startDate, endDate) { const params = new URLSearchParams({ latitude: lat.toString(), longitude: lon.toString(), start_date: startDate, // Format: YYYY-MM-DD end_date: endDate, daily: 'temperature_2m_max,temperature_2m_min,precipitation_sum,weather_code' }); const res = await fetch(`https://archive-api.open-meteo.com/v1/archive?${params}`); if (!res.ok) { throw new Error(`Historical weather API failed: ${res.status}`); } const data = await res.json(); return data.daily.time.map((date, i) => ({ date, maxTemp: data.daily.temperature_2m_max[i], minTemp: data.daily.temperature_2m_min[i], precipitation: data.daily.precipitation_sum[i], weatherCode: data.daily.weather_code[i] })); } // Usage // getHistoricalWeather(40.7128, -74.0060, '2024-01-01', '2024-01-31') // .then(history => { // const avgTemp = history.reduce((sum, day) => // sum + (day.maxTemp + day.minTemp) / 2, 0) / history.length; // console.log(`Average temperature in January: ${avgTemp.toFixed(1)}°C`); // }); ``` ### decode_weather_code Decode Open-Meteo weather codes into human-readable descriptions. ```bash # Weather code reference decode_weather_code() { case $1 in 0) echo "Clear sky" ;; 1|2|3) echo "Partly cloudy" ;; 45|48) echo "Foggy" ;; 51|53|55) echo "Drizzle" ;; 61|63|65) echo "Rain" ;; 71|73|75) echo "Snow" ;; 77) echo "Snow grains" ;; 80|81|82) echo "Rain showers" ;; 85|86) echo "Snow showers" ;; 95) echo "Thunderstorm" ;; 96|99) echo "Thunderstorm with hail" ;; *) echo "Unknown" ;; esac } # Usage decode_weather_code 61 # Output: Rain ``` **Node.js:** ```javascript function decodeWeatherCode(code) { const weatherCodes = { 0: 'Clear sky', 1: 'Mainly clear', 2: 'Partly cloudy', 3: 'Overcast', 45: 'Foggy', 48: 'Depositing rime fog', 51: 'Light drizzle', 53: 'Moderate drizzle', 55: 'Dense drizzle', 56: 'Light freezing drizzle', 57: 'Dense freezing drizzle', 61: 'Slight rain', 63: 'Moderate rain', 65: 'Heavy rain', 66: 'Light freezing rain', 67: 'Heavy freezing rain', 71: 'Slight snow fall', 73: 'Moderate snow fall', 75: 'Heavy snow fall', 77: 'Snow grains', 80: 'Slight rain showers', 81: 'Moderate rain showers', 82: 'Violent rain showers', 85: 'Slight snow showers', 86: 'Heavy snow showers', 95: 'Thunderstorm', 96: 'Thunderstorm with slight hail', 99: 'Thunderstorm with heavy hail' }; return weatherCodes[code] || 'Unknown'; } // Usage // console.log(decodeWeatherCode(61)); // Output: Slight rain ``` ### weather_alerts_and_monitoring Check weather conditions and generate alerts. **Node.js:** ```javascript async function checkWeatherAlerts(lat, lon, thresholds) { const { maxTemp = 95, // °F minTemp = 32, // °F maxWindSpeed = 30, // mph maxPrecip = 2 // inches } = thresholds; const weather = await getCurrentWeather(lat, lon, 'fahrenheit'); const forecast = await getWeatherForecast(lat, lon, 3, 'fahrenheit'); const alerts = []; // Current condition alerts if (weather.temperature >= maxTemp) { alerts.push({ type: 'high_temp', severity: 'warning', message: `High temperature: ${weather.temperature}°F` }); } if (weather.temperature <= minTemp) { alerts.push({ type: 'low_temp', severity: 'warning', message: `Low temperature: ${weather.temperature}°F` }); } if (weather.windSpeed >= maxWindSpeed) { alerts.push({ type: 'high_wind', severity: 'warning', message: `High wind speed: ${weather.windSpeed} mph` }); } // Forecast alerts forecast.forEach(day => { if (day.precipitation >= maxPrecip) { alerts.push({ type: 'heavy_rain', severity: 'watch', message: `Heavy rain expected on ${day.date}: ${day.precipitation} inches`, date: day.date }); } }); return { currentWeather: weather, forecast: forecast, alerts: alerts, hasAlerts: alerts.length > 0 }; } // Usage // checkWeatherAlerts(40.7128, -74.0060, { // maxTemp: 90, // minTemp: 32, // maxWindSpeed: 25, // maxPrecip: 1.5 // }).then(result => { // console.log(`Current: ${result.currentWeather.temperature}°F`); // if (result.hasAlerts) { // console.log('⚠️ Weather Alerts:'); // result.alerts.forEach(alert => // console.log(` - ${alert.severity.toUpperCase()}: ${alert.message}`) // ); // } else { // console.log('✅ No weather alerts'); // } // }); ``` ## Agent prompt ```text You have access to free weather APIs (Open-Meteo and wttr.in). When you need weather data: 1. For current weather and forecasts, use Open-Meteo: - Current: https://api.open-meteo.com/v1/forecast?latitude={lat}&longitude={lon}¤t=temperature_2m,weather_code - Forecast: Add &daily=temperature_2m_max,temperature_2m_min,precipitation_sum - Historical: https://archive-api.open-meteo.com/v1/archive 2. For quick weather checks, use wttr.in: - Simple: https://wttr.in/{city}?format=3 - JSON: https://wttr.in/{city}?format=j1 - Works with city names or coordinates 3. Weather parameters available: - Temperature (current, feels-like, max/min) - Humidity, precipitation, wind speed/direction - Weather codes (0=clear, 61=rain, 71=snow, 95=thunderstorm) - UV index, cloud cover, visibility 4. Temperature units: - Open-Meteo: Add &temperature_unit=fahrenheit (default: celsius) - wttr.in: Returns both Celsius and Fahrenheit 5. Best practices: - Cache weather data for 15-30 minutes - Use coordinates for accuracy (get from geocoding) - Decode weather codes to human-readable descriptions - Set reasonable alert thresholds for monitoring No API keys required. Unlimited requests within fair use. ``` ## Cost analysis: Open-Meteo vs. paid APIs **Scenario: AI agent checking weather 1,000 times/month** | Provider | Monthly cost | Rate limits | API key required | |----------|--------------|-------------|------------------| | OpenWeatherMap | **$15-50** | 60 calls/min | ✅ Yes | | WeatherAPI | **$0-10** | 1M calls/month free | ✅ Yes | | **Open-Meteo** | **$0** | **10k req/day** | **❌ No** | | **wttr.in** | **$0** | **Unlimited** | **❌ No** | **Annual savings with Open-Meteo: $180-$600** ## Rate limits / Best practices - ✅ **Open-Meteo: 10,000 requests/day** — Very generous for typical use - ✅ **wttr.in: Unlimited** — Community service with fair use - ✅ **Cache weather data** — Weather doesn't change frequently (15-30 min cache) - ✅ **Use coordinates** — More accurate than city names - ✅ **Decode weather codes** — Convert numeric codes to descriptions - ✅ **Set timeouts** — 10-second timeout for weather requests - ⚠️ **Self-host for critical apps** — Open-Meteo is self-hostable - ⚠️ **Don't poll continuously** — Weather updates hourly, not every second ## Troubleshooting **Error: "Invalid coordinates"** - Symptom: API returns error for lat/lon - Solution: Validate lat ∈ [-90, 90], lon ∈ [-180, 180] **No data returned:** - Symptom: API returns empty or null values - Solution: Check if location has weather station coverage; try nearby coordinates **Historical data missing:** - Symptom: Archive API returns no data for date range - Solution: Open-Meteo archive starts from 1940; check date format is YYYY-MM-DD **Weather code not recognized:** - Symptom: Unknown weather code number - Solution: Refer to WMO weather code standard; codes 0-99 are defined **wttr.in returns HTML instead of JSON:** - Symptom: Response is HTML page - Solution: Ensure you add ?format=j1 to get JSON response **Temperature unit confusion:** - Symptom: Unexpected temperature values - Solution: Open-Meteo defaults to Celsius; add &temperature_unit=fahrenheit if needed ## See also - [../free-geocoding-and-maps/SKILL.md](../free-geocoding-and-maps/SKILL.md) — Get coordinates for weather lookups - [../send-email-programmatically/SKILL.md](../send-email-programmatically/SKILL.md) — Send weather alerts via email - [../using-telegram-bot/SKILL.md](../using-telegram-bot/SKILL.md) — Send weather updates via Telegram