Intent

Self/home ambient. A splash without weather feels oddly austere; this is a low-value, high-delight widget that signals the tool is personal, not just technical.

Fetcher kind + safety

• `Fetcher` (cached). TTL 30 min — weather doesn't change that fast, and it keeps the wttr.in / open-meteo load polite.
• `Safety::Safe`. Host hardcoded; config-provided fields are `location` (a name like "Tokyo") and `units`, neither of which is an exfil vector. See `project_trust_model.md` — fixed-host + no credentials = Safe.

Data source

Two interchangeable backends:

• wttr.in (default). No API key, returns compact JSON on `?format=j1`, tolerant of location strings ("Tokyo", "94043", airport codes).
• open-meteo.com. No key, forecast data. Location needs lat/lon; we'd either ask the user to provide it or geocode via `open-meteo.com/v1/geocoding`.

Both hosts are hardcoded in the fetcher struct; config can't redirect.

Payload shape

`Body::Entries`:

Some renderers (`bignum`) will want a scalar `temp` — that's a layout concern, the fetcher returns the full entry set and the layout picks what to show.

Config schema sketch

```toml
[[widgets]]
id = "weather"
fetcher = "weather"

[widgets.weather]
location = "Tokyo" # name, zip, airport code; wttr.in parses loosely
source = "wttr" # "wttr" | "open_meteo"
units = "metric" # "metric" | "imperial"
```

Design questions

• Location auto-detect: wttr.in does `?format=j1` + no location → IP-based geolocation. That's convenient on a home network, misleading on VPN. Default: explicit location. Document `location = ""` as opt-in auto-detect.
• Missing location, default mode: don't auto-geolocate without opt-in — the privacy surprise ("splashboard knows where I am") beats the convenience.
• Forecast: separate `weather_forecast` widget so users can opt into the bigger payload independently.
• Icon selection: a static map from condition string → emoji. wttr.in's condition codes are stable.
• Offline: show the last cached payload with a staleness indicator ("weather (cached 3h ago)"). Don't error.

Related widgets (see #41)

• weather_forecast (3-day) — separate
• sunrise_sunset — subset that could be folded in here
• moon_phase — parallel ambient widget, different data source

Out of scope

• Hyper-local radar / precipitation maps. Wrong tool.
• Multi-location rollups (weather in 3 cities). Users wire 3 widgets.