Last updated: May 9, 2025
Delta Calendar helps you track and manage your events, metrics, and routines. This privacy policy explains how we handle your data within the app.
What: If you enable location services, Delta Calendar accesses your device’s latitude and longitude to fetch weather information using Apple's WeatherKit. Alternatively, you can manually enter a city name, which is geocoded using Apple's Core Location to obtain coordinates, and then used to fetch weather data via WeatherKit.
How: When fetching weather data, your location data (latitude and longitude) is sent to Apple's WeatherKit service. If you manually enter a city name, the city name is sent to Apple's Core Location service for geocoding, and the resulting coordinates are then sent to WeatherKit for weather data.
Storage: Your location data is not stored by us on our servers. The city history, including city names and coordinates, is saved locally on your device as part of your app data. This data is not linked to your identity.
Control: You can disable location services or use manual entry at any time.
Health Data
What: If you enable tracking for health metrics, Delta Calendar requests permission to access data from Apple’s HealthKit. This can include, but is not limited to: step count, heart rate, blood oxygen (oxygen saturation), respiratory rate, heart rate variability (HRV SDNN), VO2 max, environmental audio exposure, exercise minutes, stand minutes (used to calculate stand hours), time in daylight, sleeping wrist temperature, blood glucose, and sleep analysis data (including total sleep, core sleep, deep sleep, REM sleep, and time awake).
How: This data is fetched from HealthKit and stored locally on your device to display your health metrics within the app.
Sharing: Health data is not transmitted off your device by Delta Calendar or shared with third parties by Delta Calendar. Access is governed by your permissions in Apple's Health app.
Control: You can manage permissions for HealthKit data through Apple's Health app and disable tracking for any of these health metrics in Delta Calendar's settings to stop the app from accessing this data.
What: If you enable the chess ELO tracking feature and provide your Chess.com username, Delta Calendar uses it to fetch your ELO rating.
How: Your username is stored locally and transmitted to Chess.com to retrieve your current ELO rating, which is then saved as a metric.
Sharing: The username is not stored beyond local use or linked to other personal data, but it is sent to Chess.com when the feature is active.
Control: This feature is optional and can be disabled.
Local Data Storage
What: Delta Calendar stores your events, metrics, routines, journal entries, and city history locally on your device. This includes:
Event data: one-time events, recurring events, duration events, substance routines.
Weather metrics: Temperature, Humidity, UV Index, Precipitation, Wind Speed, Cloud Cover, Atmospheric Pressure, Moon Phase.
Health metrics: Step count, heart rate, blood oxygen, respiratory rate, heart rate variability (HRV), VO2 max, environmental audio exposure, exercise minutes, stand minutes, stand hours, time in daylight, wrist temperature, blood glucose, and various sleep analysis metrics (e.g., Total, Core, Deep, REM, Awake).
Other metrics: Chess ELO ratings.
Journal entries: Stored locally as part of the Today and Journal tab.
Location history: City names and coordinates used for weather are saved locally.
How: Data is saved in JSON files (or a similar local database format) in the app’s documents directory and is accessible only by the app on your device.
Sharing: None of this locally stored data is automatically transmitted off your device by Delta Calendar.
What: Delta Calendar allows you to export all your locally stored data, including events, metrics, routines, journal entries, and health metrics, as a ZIP file.
How: You can initiate this export through the app's settings. The ZIP file is created on your device, and you can choose to share it or store it externally.
Sharing: The app does not automatically transmit any data off your device. Any sharing of the exported data is done manually by you.
Control: This feature is optional and can be used at your discretion.
Note: The exported data may contain personal or sensitive information, such as health metrics. Please handle the ZIP file securely and be cautious when sharing it with others.
Apple's Services: For location-based features, we use Apple's Core Location for geocoding city names and Apple's WeatherKit for fetching weather data. This involves sending location data or city names to Apple's servers as described in the 'Location Data' section.
Chess.com: If you enable chess ELO tracking, your Chess.com username is sent to Chess.com to retrieve your ELO rating. No other data is shared.
Affiliate Shop: The app includes an affiliate shop tab with links to third-party websites for recommended products. Any interactions with these sites, including potential data collection, are governed by their own privacy policies. Delta Calendar does not collect or share additional data through this feature beyond providing the links.
Delta Calendar does not collect, store, or share any other personal data beyond what is described above.
We do not use analytics tools, advertising networks, or third-party SDKs that collect data from your device.
You have full control over your data in Delta Calendar. You can add, edit, or delete your events, metrics, routines, and journal entries at any time.
Disabling location services, health tracking features (including step count, heart rate, blood oxygen, and sleep duration), or chess ELO tracking stops the app from accessing or using that data.
We may update this privacy policy as the app evolves. Changes will be reflected in the "Last updated" date above.
Please review this policy periodically to stay informed.
If you have questions or concerns about this privacy policy, please email us at DeltaCalendarContact@gmail.com.