This notice distinguishes the public release from the separately labelled ČHMÚ Weather Personal build. The public build does not include the authenticated ČHMÚ mobile-app service or request permission for its domain.
ČHMÚ Weather has no advertisements, analytics or server operated by its developer, and does not ask you to sign in. It reads weather locations and unit preferences from Pebble. The current-location entry requests an approximate phone position with Location permission; fixed saved locations do not request GPS.
Requests to weather providers
Nearest forecast towns and stations are selected locally from a bundled catalogue. Public ČHMÚ graph requests identify a forecast-town ID or station ID rather than sending the phone’s raw GPS coordinates.
The public build defaults to Open-Meteo completion and Open-Meteo UV:
- Use Open-Meteo to complete missing weather data requests rain probabilities, missing weather fields and forecasts up to seven days. Choosing Open-Meteo UV requires this switch to be on; the selector never enables it automatically. When the switch is off, there are no Open-Meteo requests or cached Open-Meteo values in output, including UV fallback.
The public build enforces app-service exclusion even if settings from an older release enabled it. An old ČHMÚ UV preference becomes Open-Meteo when completion is enabled, or Off otherwise. Explicit Open-Meteo/Off preferences remain. Old app-service cached values and diagnostic readings are excluded. The public build does not obtain app-service credentials or read Pebble’s secure storage.
Open-Meteo requests send the public coordinates of the nearby forecast town, not the phone’s raw GPS position or your saved location name.
ČHMÚ station measurements and valid public ALADIN fields remain the primary sources for current temperature and hourly forecasts.
The public build declares these network domains:
| Domain | Purpose |
|---|---|
data-provider.chmi.cz |
Public ČHMÚ live station and ALADIN forecast graphs |
opendata.chmi.cz |
Backup ČHMÚ station observations |
api.open-meteo.com |
Optional additional forecast fields and extended days |
Pebble asks for the plugin’s declared network permissions through its normal permission flow. Version 1.0.1 removes the app-service domain from the public manifest.
Each provider can observe the connecting network’s IP address and the requested town, station or forecast coordinates, as with other web requests. No weather requests, credentials or location data are sent to the developer. Provider policies: ČHMÚ and Open-Meteo.
Disabling a source stops future requests for that source and excludes its cached values. A request already sent can finish, but an obsolete update does not replace readings under the new settings. UV Off omits UV; Open-Meteo may still be contacted for other enabled completion fields. Previously delivered weather remains subject to Pebble or each watchface’s own storage behavior.
Local storage and calculations
Weather responses, station choices, source settings and the latest diagnostic per location are stored locally in Pebble’s plugin storage.
The public ČHMÚ/Open-Meteo resource cache retains at most 16 records. These records include station/town IDs and may include coarse forecast-town or model-grid coordinates and other provider response metadata. Cache metadata can also contain HTTP validators (ETag or Last-Modified), the last check time and the original body-download time. They are not a raw GPS history and are not uploaded to the developer. Diagnostics contain the place and station names, measurement time and age, displayed weather, source information, original UV update time, eligible nearby station choices, status and last successful update. They do not display service credentials.
A separate bounded history retains already-past ALADIN forecast temperature and condition values for today’s Prague date: at most 16 public forecast points and 25 hourly samples per point. Records use the public point ID and coordinates, date and original forecast download time. They contain no phone GPS history or station measurements. A later model run can use them only as past forecast context. Previous-day records are removed when the history is next accessed.
Conditional GETs send a weather response’s ETag or Last-Modified value back to
the same service when rechecking it. They do not change the selected locations
or services. A 304 updates the check time without changing data ages. Weather
responses marked no-store are not persisted as reusable weather bodies.
Their values can still appear in the current reply and derived diagnostics.
An ALADIN no-store response also removes that public point’s retained forecast
context.
Personal build only: ČHMÚ app service
The separately labelled ČHMÚ Weather Personal build has its own plugin
UUID and storage, and additionally declares chmu.rails.cz internet access.
It is not included in the public PBW or Store package. This service’s
third-party access terms remain unconfirmed; attribution is not treated as
permission to use the authenticated service.
Its default settings enable Use ČHMÚ full-day forecasts and ČHMÚ UV:
- Use ČHMÚ full-day forecasts requests three-day local daily aggregates. It controls daily forecasts only.
- Choosing ČHMÚ under Preferred UV source requests clear-sky noon UV even when full-day forecasts are off. Open-Meteo or Off stops this UV channel.
- To stop all app-service requests and exclude its cached values, turn off full-day forecasts and select Open-Meteo or Off for UV.
App-service requests send the public coordinates of the selected forecast town. They do not send raw phone GPS, a saved location name or the phone’s actual Android identifier. When either channel is needed, this build creates a persistent random installation ID and obtains its own login/refresh credentials. They identify this plugin installation, and are not account credentials or credentials copied from another app. Nothing is embedded in the distributed PBW.
The installation ID is stored locally. Credentials use Pebble secure storage when available, with local plugin storage as a fallback on older runtimes. The app cache retains at most 16 additional records. The service can associate requests with the random installation ID and service session; no credentials are shown in diagnostics or sent to the developer. Disabling full-day forecasts alone does not disable ČHMÚ UV or its authentication. A request already sent can finish after a setting changes.
Local calculations and denied permissions
Feels-like temperature and sunrise/sunset are calculated inside both builds. Those calculations do not contact an additional service. Removing the plugin removes its data according to the Pebble app’s storage behavior.
If Location or network access is denied, the plugin may be unable to provide weather. It never circumvents a denied location-source permission by requesting GPS instead. Pebble’s own provider integration or a consuming watchface may retain its own cached weather or choose a fallback independently.