Privacy Policy

Privacy by construction

Your device converts your location into an approximate grid cell — roughly 7 km across — before anything is sent. That cell is the one thing Aerzeit's server ever receives about a location, and it is used only to fetch the local forecast. Your exact coordinates never leave your device, and your filter settings never leave it at all. The cell is never linked to your name, device, or account. No tracking, no analytics, no ads — ever.

What Aerzeit collects

Aerzeit's server keeps exactly two values — neither is linked to you:

H3 grid cell (~7 km across): Derived on your device by snapping a location to an H3 hexagonal grid cell at resolution 6 (about 36 km²). Your exact coordinates never leave your device. Everyone in the same cell shares the same record — it cannot be traced back to an individual.
Last request time: The time of the most recent forecast request for that cell, from anyone in it. Used only to delete records that nobody has requested for 30 days.

In the terms app stores use, this is an approximate location, collected only to make the app work, and never shared or sold.

What Aerzeit does NOT collect:

Your exact coordinates
Your name, email address, or any account identifier
Device ID, advertising identifier (Apple's IDFA or Android's advertising ID), or any persistent device token
Usage patterns, session data, analytics, or behavioral tracking
Payment or purchase information — the App Store (Apple) or Google Play (Google) handles every subscription payment. The app checks your subscription on your phone; nothing about your purchase reaches Aerzeit's server
Your temperature target, rain threshold, or notification schedule — these live only on your device and never leave it

Why we collect it

One purpose only: to fetch the 48-hour weather forecast for your grid cell from the Aerzeit backend. The grid cell is the minimum unit of data needed to answer the question "what is the weather near me?" — nothing more is collected because nothing more is needed.

How long we keep it

Server (grid cell + last-request time): deleted automatically once nobody has requested a forecast for that cell for 30 days. If you stop using the app, your requests stop, and the cell's record is deleted 30 days after the last request from anyone in that cell.

On-device data (your settings, saved locations, notification history): stored in the app's private storage on your phone. Deleted when you delete a location or uninstall Aerzeit.

Sub-processors

Aerzeit uses these providers. None of them receives anything that identifies you:

Cloudflare (network infrastructure): Hosts the Aerzeit backend. Cloudflare's network sees transient HTTP metadata (IP address) for rate-limiting; Aerzeit does not write IP addresses to its database. See Cloudflare's privacy policy.
Google Cloud (weather server): Hosts Aerzeit's own weather server, which receives only a grid cell's centre coordinates. See Google's privacy policy.
Open-Meteo (weather and air-quality data): Provides forecast data. Aerzeit's server requests it using only a grid cell's centre coordinates — no user identity is transmitted. See Open-Meteo's terms.
Google Pollen API (pollen data outside Europe): Where the European pollen model has no data for a cell, Aerzeit's server requests pollen for the cell's centre coordinates — no user identity is transmitted, and the result is kept for 24 hours per cell. See Google's privacy policy.
Apple (App Store) and Google (Google Play) (subscription payments): Each store processes the payment directly. Aerzeit never receives your payment details, billing information, or any record of your purchase. See Apple's privacy policy and Google's privacy policy.

Your rights

Regardless of where you're located, you have the following rights over your data:

Right of access: Your locations and settings are on your phone, and you can see them in the app. On iPhone, open any location and tap Export my data to save a copy of everything the app holds on your device. Aerzeit's server holds nothing linked to you, so there is no personal record there to retrieve; you are welcome to email us with any question.
Right to erasure: Delete a location in the app, or uninstall Aerzeit, to remove its data from your phone. Aerzeit's server holds only shared area records, which are not linked to any person and are deleted automatically after 30 days without requests from anyone in that area. To have one deleted sooner, email us the city or grid cell: we will delete that record, confirm it, and then delete your email. The record is created again whenever anyone in that area next requests a forecast.
Rectification, restriction, portability, objection: Contact us at the address below. We respond within 30 days.

To exercise any right, email support@aerzeit.app.

Data controller

Operator: Samuel Harrold, Indianapolis, Indiana, USA
Privacy contact: support@aerzeit.app

Aerzeit is operated by an individual based in the United States, not a registered company. If you are located in the EU or UK and have a data protection concern this policy doesn't address, please contact us directly at the address above — we will respond and address it, even though we do not currently have a formally designated EU representative under GDPR Article 27.