What cold actually does
The experience description says the higher you climb, the colder it gets. Cold is not scenery. Once you pass your limit, health starts falling, and staying in that band makes the loss faster. A Too cold warning is the cue to leave.
One early report placed that warning near 280 meters on a low warmth stat. A later recorded session, after some upgrades, could work around 308 meters and saw the warning when pushing toward about 380 meters. Those are session ceilings. They are not a published altitude table.
Climb Higher versus the other buys
The upgrade station labels cold tolerance Climb Higher and backpack capacity Carry More. The experience description names the same three lines: warmth, pickaxe, and backpack.
| What ended the run | Buy next | What should change |
|---|---|---|
| Too cold, or health falling, before the bag is full | Climb Higher | The safe ceiling moves up |
| Rock or a crystal will not break, or a pickaxe-level warning appears | Next pickaxe | Resistant targets start breaking |
| Backpack Full while you are still safe | Carry More | Heavier crystals and longer trips fit |
Warmth does not have a published speed bonus. It buys time in the cold band. If the bag fills while you still have warmth left, another warmth level will not fix that trip.
Leave with the load
Go home before health is gone. Guides describe a return-to-base control. Whether a downed climber keeps the bag is not published, so do not test it with a good haul.
After you can survive the band you want, climb the outside of the mountain to that height and start mining there. Tunneling up from the bottom spends the warm window on low-value rock.
Fall damage is separate from cold. Jumping from a high ledge can injure you. The No Fall Dmg pass is a convenience, not a key to a zone.