When speaking about the interior lighting the temperature of the light is one of the important aspects when choosing a proper light source. Beyond the RGB lights the temperature is commonly understood as the colour of the light. Or the colour of the "white" light.
The temperature of the light is measured in Kelvins. Below 2000K are the warm lights such as candlelight or bonfire. Average overcast daylight is around 6500K and cold winter day when the sun is shining and the sky is blue it can reach over 10 000K.
So higher the temperature gets the association of such light is getting colder. From warm fire to the cold winter day. Maybe because traditionally the sources of such high temperature light sources have been so hot that we have only been able to observe them from afar. The colder light sources on the other hand have been those we have seek'd warmth.
This has changed in the era of the LED lights. They are able to produce light of any temperature without producing any noticeable amount of heat. The cold light is still cold, but now the warm light doesn't produce any comforting heat either.