What about negative values, please, e.g. -80 °C as start?
The existing range questions already support negative values. It’s even possible to create both ascending and descending ranges, like 1…10 or 10…1, and the new implementation will retain this functionality.
You can now specify labels for the start and end of a range as well as for other ticks! Learn more in ODK Collect v2026.2: range question type gets labels and other configurability
Note that labels are currently truncated aggressively on narrow devices so @Toon_Driesen's original example might not be supported. If you have additional needs around range not served by the new additions, feel free to continue the conversation here.