Temperature is a measurement, a number on a scale showing how hot or cold something is; heat is the energy or sensation of warmth itself. A memory hook: a thermometer reads temperature, but you feel heat radiating from the oven.
The core difference
Temperature is the measurement of hot or cold, while heat is the energy or warmth being measured.
- temperature — a measurement of how hot or cold something is: The temperature dropped below freezing overnight.
- heat — the energy or sensation of high temperature; warmth: The heat from the oven filled the whole kitchen.
How to tell them apart
Temperature comes from the Latin temperatura, sharing a root with "temper", originally about a proper mixture or proportion. Heat has a much older, plainer Germanic root, an ancient word for warmth related simply to "hot". The two words diverged early: one is about balance and measurement, the other about raw sensation.
The mix-up tends to show up in cooking and weather talk, where people say a day is "very hot" when they mean the temperature is high, or ask to "turn up the heat" when they mean raise the temperature on a dial. Both words also stretch well beyond physical warmth: temperature can describe a fever, as in a child sent home from school with a temperature, while heat can describe intense emotion, as in the heat of an argument, or a qualifying round in a race.
