Apple Watch Wrist Temperature only logs sporadically despite Sleep Focus and correct setup

Hi everyone,

my Apple Watch records Wrist Temperature only once in a while. Some nights it logs fine, other nights there is no entry at all, even though my setup and routine are the same.

Example that worked:

Oct 2–3 (start 23:14, end 06:39). Wrist temperature ~36.16 °C, skin temp ~35.11 °C.

Many other nights: no record created.

Devices / versions:

– Apple Watch (hardware identifier Watch7,12, so it’s Ultra 3)

– iPhone paired; both on the latest iOS/watchOS

What I’ve already tried (no change):

Sleep Focus ON on the Watch for the entire night (manually enabled) and sleep ≥ 4 h.

Low Power Mode OFF overnight.

Toggled Wrist Temperature permission OFF/ON, then restarted the Watch.

Focus mirroring: iOS “Share Across Devices” ON; Watch app → General → Focus → “Mirror my iPhone” ON.

no third-party sleep apps)

Strap fit: snug and stable

Gave it multiple consecutive nights to rebuild the baseline.

Verified the Health data source shows Apple Watch.

Deleted and re-created the Sleep schedule (sometimes helps for 1–2 nights only).

Watch was originally paired as NEW (no restore from backup). I’d prefer not to wipe/repair again.

Wrist Temp appears randomly—works one night, then missing for several nights, under identical conditions.