Why metal feels colder than wood

Metal feels colder than wood because it carries heat away from your skin faster, so the skin itself cools. A thermometer on the wood and a thermometer on the metal can agree while your hand insists they differ.

The metal is not a colder object by nature, and cold is not a substance stored inside it. If both have been sitting in the same room, they share one temperature until your hand starts a new flow of heat.

The mechanism is more particular than the slogan. Skin is warmer than a typical room, so on contact heat flows out of the hand into whatever you touch. In metal that heat races inward, the surface under your fingers stays near room temperature, and the nerve endings report a chill.

Follow it one step further. Wood conducts heat poorly, so the spot under your fingers warms toward skin temperature and then the flow slows. The nerves are reporting how fast heat is leaving, not a temperature label printed on the material.

The case worth keeping in mind is specific. A metal bench and a wooden bench left outside on the same night feel nothing alike at dawn. The metal one keeps robbing heat from you, while the wooden one lets a thin layer at the surface come up toward your skin.

That case has a boundary. The same conductivity that makes cool metal feel cold makes hot metal feel hotter than hot wood. A metal handle and a wooden handle left in one sunlit car are a fair test, and the metal wins in the painful direction too.