# Weather Feed: Kościelec & Chrzanów

> Multi-source weather, air quality and IMGW alerts exposed as change-oriented Atom feeds and JSON state.

Weather Feed is a Cloudflare Worker that combines several weather sources for **Kościelec / Chrzanów** and publishes meaningful changes instead of repeating nearly identical readings.

## What it combines

- three point-weather sources reduced to median + spread,
- IMGW meteo alerts for powiat chrzanowski,
- IMGW hydro alerts for małopolskie,
- air quality,
- a nearby IMGW station as reference context.

## Endpoints

| Endpoint | Purpose |
| --- | --- |
| `GET /feed.atom` | all meaningful change entries |
| `GET /warnings.atom` | IMGW warning-only feed |
| `GET /state.json` | latest ensemble, warnings, air quality and station context |
| `GET /healthz` | health/staleness check |
| `GET /` | human-facing page |

## Change-oriented output

Current-condition entries are emitted for notable condition changes, temperature shifts of at least 3 °C, or precipitation start/stop. Forecast entries focus on meaningful maximum-temperature revisions and 50% rain-probability crossings.

A partial IMGW outage preserves the last known warning state for the failed category rather than inventing a false all-clear.

## Deploy

```bash
npm install
wrangler secret put OPENWEATHER_KEY
wrangler secret put VISUALCROSSING_KEY
npm run check
wrangler deploy
```

Open-Meteo and IMGW require no key. If keyed providers are absent, the Worker can continue in a degraded mode.