Colour psychology studies how colours influence mood and behaviour, with warm and cool colours widely recognized for their differing effects. Warm colours like red and orange evoke feelings of energy and stimulation, while cool colours like blue and green create a calming and relaxing effect. This essay will discuss the psychological impact of both warm and cool colours, providing real-world examples of their use. The effects of these colour categories will be compared and contrasted to highlight their influence on human emotions and behaviour.