Privacy policy and support
Last updated 7 September 2026
Questions, bug reports and feature requests are all welcome, and they reach a person rather than a queue.
Email: collinlorenz@gmail.com
If you are reporting something that looks wrong in the forecast, the place name and roughly when you saw it is usually enough to find it.
Kelvin has no accounts, no analytics, no advertising and no tracking of any kind. There is no server that belongs to Kelvin, and so there is nowhere for your information to be collected to.
This policy describes exactly what the app does with the little information it handles. It was written from the app's own source code — specifically, from the complete list of network requests it is able to make.
If you allow it, Kelvin reads your device's location so it can show the weather where you are. You can refuse, and the app still works — you add places by name instead.
A forecast is fetched for a place, so the coordinate is part of the request. It is sent to the weather and map services listed below in order to get an answer back. It is not sent anywhere else, it is not stored on any server belonging to Kelvin — there isn't one — and it is never attached to your name, your device, an advertising identifier or any account, because Kelvin has none of those things to attach it to.
Saved places and your last known forecasts are stored on your device only, so the app can open on real weather when you have no signal. Deleting the app deletes them.
Units, appearance, notification choices and your comfort range are stored on your device and in your private iCloud key–value store, so they follow you to your other devices. They are readable only by you and by Kelvin.
If you buy the one-off unlock, the purchase is handled entirely by Apple. Kelvin never sees your payment details, your name or your Apple Account. It asks Apple only whether this Apple Account has bought the unlock.
Warnings, rain alerts and comfort-window notices are scheduled on your device from forecast data the app already holds. No push server is involved and no device token is sent anywhere.
Each of these receives a latitude and longitude in order to return weather or a map tile. None receives your name, your device identifier, or anything that identifies you. Each has its own privacy policy, and Kelvin has no control over their practices.
| Service | What it provides |
|---|---|
| Apple WeatherKit | The forecast itself |
| Open-Meteo | Ensemble forecasts, air quality, precipitation and wind fields |
| RainViewer | Rain radar imagery |
| NOAA / National Weather Service | Warnings, watches and advisories |
| National Hurricane Center | Tropical storm tracks |
| NASA GIBS (Earthdata) | Satellite imagery |
| Iowa State Mesonet | Additional radar imagery |
| Esri / ArcGIS | Wildfire perimeters |
| World Air Quality Index | Air quality — only if you add your own key |
| OpenWeatherMap | Optional map layers — only if you add your own key |
The last two are used only if you choose to paste your own free API key into Settings. Without a key, Kelvin never contacts them.
Kelvin collects nothing, so it collects nothing from children. It is safe for all ages.
If this policy changes, the date at the top changes with it. Material changes will be noted in the App Store release notes.