High air temperatures during periods of excessively hot weather can seriously affect human health and well-being. Towns and cities often have higher air temperatures than surrounding rural areas, a phenomenon called the ‘urban heat island effect’. Trees and greenspaces can play an important role in reducing the negative impact of the urban heat island effect on urban communities, in addition to providing a wide range of other ecosystem services. To maximise its benefit, the creation and retrofitting of greenspace needs to incorporate strategies that prioritise the tree species that can provide the most cooling. There is also a need to ensure that trees and greenspace are given the conditions they need to achieve their full potential in terms of growth and function. Research into the cooling potential of different species and greenspaces typologies has advanced in recent years. Application of this knowledge can help our cities adapt to the changing climate.