Support
Questions, bug reports, and feedback go to thermalstate@proton.me. A screenshot of the main screen helps, since it shows your device model and iOS version.
Understanding the readings
What do the four states mean?
They come straight from iOS, which reports one of four thermal levels:
- Nominal: normal operating temperature.
- Fair: slightly elevated. Usually nothing to worry about.
- Serious: hot enough that iOS may reduce performance to cool down.
- Critical: iOS is significantly limiting performance until the device cools.
Why doesn’t it show a temperature in degrees?
iOS doesn’t give apps access to the device’s temperature sensors. The thermal state is the most detailed information Apple provides, so Thermal State reports it rather than inventing a number.
Why do some numbers differ from other apps or Settings?
Apps measure storage and memory in different ways. Some count cached files that iOS can clear on its own as free space, and some use 1,000 bytes per kilobyte while others use 1,024. Physical RAM can also read slightly differently from the advertised amount. Small differences are normal.
Can Thermal State cool my device down?
No. It tells you how warm things are; it does not do anything about it. To help your device cool off, move it out of direct sunlight or a hot car, close demanding apps like games or navigation, take off a thick case, and unplug it if it’s charging.
Widgets and settings
How do I add a widget?
- Home Screen: touch and hold an empty area, tap Edit, then Add Widget. Search for Thermal State and add the medium widget.
- Lock Screen: touch and hold the Lock Screen, tap Customize, then choose Lock Screen. Tap the date above the time for the inline widget, or the area below the time for the circular one.
Why is the widget sometimes out of sync with the app?
iOS decides how often widgets refresh in order to save battery, so a widget can trail the app by several minutes or more. Open the app for a live reading.
What does Keep Screen Awake do?
It stops the screen from auto-locking while Thermal State is open. Useful for keeping an eye on things, though a screen that stays on uses more battery and, fittingly, adds a little heat.
Can I change the colors?
Yes. In the app’s Settings, choose from several color schemes for the four states, including Classic Heatmap Spectrum and High-Contrast LED.
Does it work on iPad?
Yes. Thermal State runs on both iPhone and iPad.
Privacy
Thermal State collects only anonymized usage data and never anything that identifies you. The full details are in the Privacy Policy.