A hot cup of coffee left in a cool room will cool down because the room is colder than the coffee.
A person standing outside on a cold frosty day will lose heat and so cool down.
On a hot sunny day you will warm up if you stand outside because you are receiving more heat energy from the Sun than you are emitting to the surroundings.
Leaving the door of a fridge open will allow the contents to warm up because they are colder than the room.
| An object will cool down if its temperature is greater than the temperature of its surroundings. |
The bigger the difference in temperature between and object and its surroundings the faster it will cool down.