Interactive Weather API Lab
Execute live API requests directly in your browser and inspect response latencies & JSON payloads
Free Weather APIs Comparison Matrix
Comparing forecast horizons, free quotas, authentication rules, and models
| Provider | Requires Key? | Forecast Range | Free Quota | Underlying Models | Best For |
|---|---|---|---|---|---|
| Open-Meteo Built-in | ❌ No Key | Up to 16 Days | 10,000 requests/day free | ECMWF, GFS, ICON, GEM | Global 7-14 day outlooks, zero setup |
| National Weather Service | ❌ No Key | 7 Days | Unlimited (Public Domain) | NOAA NWS High-Res Grid | US locations & narrative forecasts |
| WeatherAPI.com | ✅ Free Key | Up to 14 Days | 1,000,000 requests/month | Multi-source blended | Air quality, astronomy & alerts |
| OpenWeatherMap | ✅ Free Key | 5 to 8 Days | 1,000 calls/day (One Call) | Proprietary ML Model | Standard developer workflows |
| Tomorrow.io | ✅ Free Key | Up to 14 Days | 500 calls/day (25/hr) | Mesoscale Radar & Satellite | Minute-by-minute rain alerts |
| PirateWeather | ✅ Free Key | 7 Days | 10,000 requests/month | NOAA HRRR & GFS | Dark Sky JSON replacement |
| Visual Crossing | ✅ Free Key | Up to 15 Days | 1,000 records/day | Global Climatology & GFS | Historical + 15-day forward outlook |
Top 3 Free Weather APIs In-Depth
Architecture overview and production integration tips
Open-Meteo
open-meteo.comThe premier open-source meteorological API for modern web applications. Automatically downscales weather models from NOAA and ECMWF to a 1-11 km grid resolution.
- Forecast Range: 16 Days Daily + Hourly
- Authentication: None (Open Access)
- Rate Limit: 10,000 calls / day
- Geocoding: Free Built-in API
National Weather Service
weather.gov / NOAAThe official meteorological API of the United States government. Offers 7-day period forecasts, high-impact storm advisories, and human-written meteorological discussions.
- Forecast Range: 7 Days (14 Half-Day Periods)
- Authentication: User-Agent Header Required
- Cost: 100% Free (Public Domain)
- Coverage: United States & Territories
WeatherAPI.com
weatherapi.comMassive free allowance of 1,000,000 monthly API calls. Provides 14-day forecasts, astronomy data, sports schedules, and real-time precipitation radars.
- Forecast Range: 3 to 14 Days
- Authentication: Free API Key Required
- Free Quota: 1,000,000 calls / month
- Bonus Features: Moon phases & Air Quality
How to Implement a 7-Day Next Week Weather Request (Vanilla JS)
Copy and paste this snippet into any webpage or application script to fetch next week's temperature and precipitation data without any API key:
async function getNextWeekWeather(lat = 40.7128, lon = -74.0060) {
const endpoint = `https://api.open-meteo.com/v1/forecast?latitude=${lat}&longitude=${lon}&daily=weathercode,temperature_2m_max,temperature_2m_min,precipitation_probability_max¤t_weather=true&timezone=auto`;
const res = await fetch(endpoint);
const data = await res.json();
// Daily forecast arrays for the next 7 days
const dates = data.daily.time;
const maxTemps = data.daily.temperature_2m_max;
const minTemps = data.daily.temperature_2m_min;
const rainProb = data.daily.precipitation_probability_max;
console.log("Next Week Outlook:", { dates, maxTemps, minTemps, rainProb });
return data;
}
Want a Deeper Technical Comparison?
Read our full atmospheric engineering benchmark detailing latency, accuracy against NOAA ground stations, and ensemble probability models.
Read Full Weather API Benchmark Article →