Privacy Policy for Wassertemperatur (watchOS and iOS)
Last updated: July 16, 2026
1. Introduction
Wassertemperatur helps you log your dives, swims, and dips with temperature, depth, and duration. This privacy policy explains what data is processed, how it is stored, and what role Apple services play. Wassertemperatur is designed to collect as little personal data as possible: there are no servers of our own, no accounts, no tracking, and no advertising.
2. Data collection and processing
a) Dive measurement data: When you enter the water, the app uses your Apple Watch's depth and temperature sensor to measure water temperature, dive depth, and duration. These values are saved as a dive in your logbook.
b) Location and weather data (optional): Right after you surface, if you have granted location permission, the app requests your approximate location once to load the current weather. Coordinates and the name of the body of water are only saved if you enable "Save Location" in Settings (default: off).
c) Health data (optional): If you enable Apple Health import, the app reads water temperature values from your swim workouts via HealthKit. If you enable Apple Health export, the app writes your saved dives to Apple Health as water temperature entries.
d) CSV export and share graphics: You can optionally export your dives as a CSV file or share individual measurements as a graphic. These files are only created and shared when you trigger this yourself via the share function.
e) Feedback by email: If you contact us via "Send Feedback," your mail app transmits your message, including technical details (app version, iOS version, device model), to joe@waldow.app.
3. Data storage and synchronization
Local storage: Dive measurement data is first stored locally on your Apple Watch and transferred directly to your paired iPhone via Apple WatchConnectivity.
iCloud backup (iOS only): On iPhone, the app additionally syncs your dives to your private iCloud database (CloudKit), so they are preserved if you switch devices or reinstall the app. This data is only accessible with your Apple ID and cannot be viewed by the developer or by Apple. The Apple Watch itself does not use iCloud backup; it intentionally stays local.
4. Location and weather data (Apple WeatherKit)
Weather data (outside temperature, conditions) comes from Apple WeatherKit. Your approximate location is transmitted to Apple once for this purpose. Apple's privacy policy applies; see Apple Weather's legal attribution. You can revoke location permission at any time in your system settings.
5. No advertising, no tracking, no third-party analytics
Wassertemperatur uses no advertising SDKs, no third-party analytics or tracking services, and no advertising IDs. Your measurement data is never sold or used for advertising purposes.
6. Data deletion and user control
You can delete individual dives in the app at any time, on the Watch or on the iPhone. Deletion is propagated to the other device. Deleting the app removes all local data; the iCloud backup is also removed once it is deleted from the last device. For Health data, you can adjust permissions at any time in iOS Settings or in the Apple Health app; the app can only delete entries it created itself.
7. Your rights
You have the rights to access, rectification, erasure, restriction of processing, data portability, and objection (Art. 15 to 21 GDPR). Since Wassertemperatur does not transmit data to the developer, the developer generally holds no personal data about you, except for emails you send yourself. For data processed through Apple services such as iCloud, HealthKit, or WeatherKit, please refer to your device settings or to Apple. You also have the right to lodge a complaint with the competent data protection supervisory authority.
8. Changes to this privacy policy
This privacy policy may be updated from time to time. The version published on this page at any given time governs.
9. Controller
Wassertemperatur is developed and maintained by:
Joe Waldow
Hasenbusch 52
25335 Elmshorn
Germany
Contact: joe@waldow.app