HKQuantityTypeIdentifierAppleSleepingWristTemperature — reading Apple wrist temperature
HKQuantityTypeIdentifierAppleSleepingWristTemperature reads like a fever chart and is nothing of the kind — it is a deviation, centred near zero.
Open your file
Drop your file here
export.zip straight from the Health app — do not unzip it
No account. No upload. The file is read on this device and never leaves it.
Nothing has been sent anywhere. 0 requests to this site, for the page's own code.
A deviation, not a temperature
Apple does not export an absolute skin temperature here. After a baseline period, the Watch reports each night’s sleeping wrist temperature as a deviation from your personal baseline — a small number, often within a few tenths of a degree either side of zero, that can be negative. Reading it as an absolute body temperature (and alarming at a reading in the thirties) is a category error: the identifier measures change, not level.
Why it cannot be compared to a thermometer
Because the baseline is personal and unstated in the value, your small positive reading and someone else’s are not the same underlying temperature, and neither maps to a clinical reading. We map this identifier to a delta kind for exactly that reason; the fuller argument is on absolute versus relative skin temperature.
This identifier is one of dozens. The Apple Health data dictionary lists every identifier this parser reads, with its canonical type and unit.