This review evaluates the existing studies of blue, green, and grey interventions based on field measurements and modelling aiming to quantify the cooling impact that reduces outdoor heat stress. Based on findings from literature, it is concluded that water bodies can reduce the mean air temperature (Ta) by 3.4 degrees C and universal thermal climate index (UTCI) by 10.7 degrees C, while natural vegetation can improve Ta by 2.3 degrees C and physiological equivalent temperature (PET) by 10.3 degrees C during summer. Vertical greenery systems (VGS) provide cooling effect of Ta up to 4 degrees C, whereas architectural shades reduce it by approximately 3.8 degrees C and PET up to 6.9 degrees C under shade structure.