Clima — Weather App

Everything the Clima weather app needs to run, consolidated in one folder — including the UI. No Node.js, no build step, no dependencies: just Python 3.

weather-app/
├── backend/          Python weather service (port 5050) — API + serves the UI
│   ├── app.py        the whole server: static frontend + JSON API
│   ├── dev.py        optional stdlib supervisor (auto-restart on .py change)
│   ├── daemon_start.py  double-fork daemon launcher (used in the sandbox)
│   ├── package.json  only used by the sandbox `bun run dev` flow (optional)
│   └── .last_good/   disk-persisted "last good" payloads (stale fallback)
├── frontend/         the built-in UI — plain HTML/CSS/JS, zero build step
│   ├── index.html
│   ├── styles.css    4 themes: minimal · dark · paper · retro CRT (+ auto)
│   └── app.js        full feature set (see below), same as the Next.js app
├── logo.svg          the Clima logo (also served as favicon)
└── README.md         this file

Run it

cd weather-app/backend
python3 app.py

Then open http://localhost:5050 — the full app is served right there at /.

Stop with Ctrl+C. Nothing else to install.

Features

• Current conditions: temperature, feels-like, humidity, wind speed + direction (with gusts), pressure + 3h trend, cloud cover, UV, sunrise/sunset
• Weather alerts: severity-ordered banner for thunderstorms, damaging gusts (62/90 km/h), heavy rain (8/15 mm per 24 h), extreme heat/cold
• Today's insights: rule-based "good to know" chips (rain timing, vs-yesterday, UV, wind, temperature swing, muggy, precipitation total)
• Hour-by-hour strip (48h) with rain probability bars
• Temperature trend chart context via the hourly strip + rain outlook (next-12h probability bars, peak marker, expected accumulation)
• Precipitation nowcast: observed past 6 h vs forecast next 12 h on one shared scale with a NOW divider
• Best time outside: 12-hour outdoor-comfort score strip + best-window recommendation chips
• Wind compass with Beaufort force, gusts and direction dial
• Daylight arc with sun position, daylight-left % and moon phase
• Past 7 days history chart (high/low range bars, rain days, week stats)
• Air quality: European AQI color-banded gauge + PM2.5 / PM10 / O₃ / NO₂
• Ambient effects: rain / snow / stars / fog / clouds / lightning + a warm glow near sunrise & sunset (all disabled for reduced-motion users)
• Compare favorites: side-by-side modal with hottest/coldest/wettest badges
• 15-day forecast with temperature range bars (3-day when running on backup data)
• City search (Open-Meteo geocoding) + "use my location" + / search shortcut
• Favorites: pin cities, live temps on chips, rain/wind alert dots
• Share button (native share sheet or clipboard summary)
• °C/°F, km/h ↔ mph, mm ↔ in units
• 5 theme options: Minimal, Dark, Paper, Retro CRT (scanlines + phosphor glow), and Auto (light by day / dark by night, based on the selected city's sun state)
• Remembers your city, favorites, units and theme (browser localStorage)
• Auto-refresh every 10 minutes with a visible countdown, local clock at the forecast location

Resilience (why the app survives rate limits / outages)

Open-Meteo (free tier) is rate limited per IP; the daily quota can run out (HTTP 429). The backend therefore:

1. Caches every upstream response for 15 minutes.
2. Retries with exponential backoff (honouring Retry-After) on 429/5xx.
3. Serves stale data: the last successful payload per location is stored in memory AND on disk (.last_good/); if both providers fail, up to 24h-old data is served marked stale: true (the UI shows a "saved data" banner). A 60s per-key cooldown prevents retry storms while the upstream is down.
4. Falls back to wttr.in: when Open-Meteo is quota-exhausted, forecast payloads are rebuilt from wttr.in (free, no key) and marked degraded: true (3-day / 3-hourly resolution, rain probability kept, no history/nowcast). The UI shows a "backup data" banner and the daily card becomes "N-day forecast (backup feed)".

Raw upstream errors never reach the UI — failures map to friendly messages.