Source Player Core pg. 444

Effects with this trait deal cold damage. Creatures with this trait have a connection to magical cold.

The Cold trait marks effects that deal cold damage, and creatures with the trait have a special connection to magical cold. Cold is one of the main energy damage types, alongside acid, electricity, fire, and sonic; rules describe it as damage that “freezes material by way of contact with chilling gases and ice.”

Cold damage follows the standard four‑step damage process: roll damage, determine damage type, apply immunities/weaknesses/resistances, then reduce Hit Points by the remaining amount. A creature immune to cold ignores cold damage entirely, while resistance to cold subtracts a fixed amount from every separate instance of cold damage. Weakness to cold adds its value to each instance of cold damage, and if an effect has multiple traits (for example, “cold and vitality”), you apply the single highest relevant weakness value from those traits.

Cold is often paired with persistent cold damage, written as “X persistent cold damage,” representing frostbite, encasing ice, or lingering chill. Persistent damage of this kind triggers at the end of each of your turns, with a new roll each time; afterward you attempt a DC 15 flat check to see if the condition ends, possibly aided by allies scraping away ice or adding warmth. Environmental rules treat severe cold as a hazard that can inflict damage or fatigue over time, and many cold‑themed archetypes or feats give cold resistance and downgrade environmental cold one step in severity.

In Starfinder 2e, cold damage is defined similarly—freezing material through chilling gases and ice—and interacts with space rules: while in a vacuum, creatures become immune to persistent cold and fire damage, so ongoing freezes extinguish even if an initial cold hit is still possible.