Apple watch 10 is not measuring the wrist temperature
After continuous usage of more than 20 days, it is still not showing wrist temperature. What needs to be done
Apple Watch Series 10, watchOS 11
Are you using a Sleep Schedule?
Did you already have a look at this related article?
Track your nightly wrist temperature changes with Apple Watch - Apple Support
It might also not be available in all regions:
watchOS 26 - Feature Availability - Apple