# MeteoModels

> Free weather forecast model comparison tool — compare GFS, ECMWF, ICON, AROME, ARPEGE,
> HRRR, MeteoBlue, UKMO, GEM, HARMONIE and more side by side, in real time, for any location worldwide.

URL: https://meteomodels.vercel.app/
About: https://meteomodels.vercel.app/about.html

## What is MeteoModels?

MeteoModels is a browser-based weather application that shows predictions from up to 10+
numerical weather prediction (NWP) models simultaneously for any location worldwide.
Instead of relying on a single forecast, users see all major models at once — including
temperature, precipitation probability, wind speed, humidity, UV index and more.

It is free to use, requires no account or sign-up, and works as a Progressive Web App (PWA)
installable on any device.

## Weather Models Compared

| Model        | Organisation              | Resolution | Coverage         |
|--------------|---------------------------|------------|------------------|
| GFS          | NOAA (USA)                | 0.25°      | Global           |
| ECMWF IFS    | ECMWF (Europe)            | 0.1°       | Global           |
| ICON Global  | DWD (Germany)             | 0.1°       | Global           |
| ICON EU      | DWD (Germany)             | 0.0625°    | Europe           |
| HRRR         | NOAA (USA)                | 3 km       | CONUS (USA)      |
| AROME HD     | Météo-France              | 1.3 km     | France + borders |
| AROME 2.5 km | Météo-France              | 2.5 km     | France + borders |
| ARPEGE EU    | Météo-France              | 0.1°       | Europe           |
| MeteoBlue    | MeteoBlue (Switzerland)   | —          | Global           |
| UKMO         | UK Met Office             | 0.09°      | Global           |
| GEM          | Environment Canada        | 0.15°      | Global           |
| KNMI HARMONIE| KNMI (Netherlands)        | 5.5 km     | NW Europe        |
| DMI HARMONIE | DMI (Denmark)             | 5.5 km     | N Europe         |

Ensemble probability plumes are available for GFS ENS (30 members), ICON ENS (39),
ECMWF ENS (51), GEM ENS (20) and AROME HD (deterministic reference).

## Key Features

- **Multi-model ensemble**: up to 10+ NWP models compared side by side
- **Location-adaptive model weighting**: models are automatically scored and weighted by
  accuracy for the requested location — high-resolution regional models (AROME for France,
  HRRR for USA, HARMONIE for N/W Europe) receive higher weights when they cover your area
- **Real-time PWS observations**: actual measurements from the nearest Weather Underground
  personal weather station within 2 km — temperature, humidity, wind, pressure, UV
- **Multi-station rain consensus**: cross-validates rain detection across all active
  weather stations within 2 km; reports `station_rain` (boolean), `rain_confidence` (0–1),
  `stations_checked` and `stations_raining`
- **Official weather alerts**: MeteoAlarm (Europe) and NWS (US) alerts filtered to exact location
- **Clothing advice**: practical daily outfit recommendations in 5 languages, based on ensemble
- **Hourly and 14-day daily forecasts** with precipitation, wind, humidity, UV
- **Ensemble probability charts**: visualise forecast uncertainty across 141+ model members
- **Interactive map** (OpenStreetMap) and nearby webcam view
- **PWA**: installable on iOS/Android, works offline after first load

## Public REST APIs

### Model Ensemble API
```
GET https://meteomodels.vercel.app/api/models?lat=LAT&lon=LON
```
Returns a weighted multi-model ensemble for the given coordinates. Selects the best models
for the location, applies location-adaptive weights, and returns hourly + daily forecast data.
Cache: 30 min. Rate limit: ~1,250 calls/day (Open-Meteo free tier).

### Real-Time Observation API
```
GET https://meteomodels.vercel.app/api/observation?lat=LAT&lon=LON
```
Returns current observations from all active Weather Underground PWS stations within 2 km,
including a multi-station rain consensus. Fields: `station_rain`, `rain_confidence`,
`stations_checked`, `stations_raining`, full `observation` block per station.
Cache: 5 min. Rate limit: ~8,300 calls/day (WU free tier).

Both APIs return JSON and support CORS. No authentication required.

## Languages

Catalan · Spanish · English · French · German

## Data Sources

- Open-Meteo (open-source weather forecast API, https://open-meteo.com)
- Weather Underground / The Weather Company (PWS real-time observations)
- MeteoAlarm (EU official weather warnings, https://www.meteoalarm.org)
- NWS (US National Weather Service alerts)
- OpenStreetMap / Nominatim (geocoding)
- Open-Meteo elevation API

## Frequently Asked Questions

**What is the difference between MeteoModels and a regular weather app?**
Most apps show one forecast from one model. MeteoModels shows all major models simultaneously
with a weighted ensemble average. You can see where models agree (high confidence) and where
they diverge (uncertain forecast) — essential for planning around borderline weather.

**How does MeteoModels weight models?**
Each model gets a base score, a regional bonus (higher for high-resolution regional models
covering your area), a resolution bonus (finer grid = better terrain capture), and a terrain
sensitivity modifier (for mountainous locations). Final weights are normalised to 100%.

**How accurate is the rain detection?**
The `station_rain` flag in /api/observation is true if any PWS within 2 km reports
precipRate > 0 mm/h in an observation less than 15 minutes old. The `rain_confidence` score
(0.0–1.0) represents the fraction of all active nearby stations confirming rain.

**Is MeteoModels free?**
Yes — completely free, no account required. The project is supported by the community
via Ko-fi (https://ko-fi.com/marcpeleja).

## Author

Marc Peleja — https://meteomodels.vercel.app/about.html