In summer daytime, air temperature under the large green canopy is lower than its surroundings. We call this space "Cool Spot". Some sets of meteorological elements were measured in and around urban parks in Osaka in August 1992 to clear thermal effects of green canopy. The correlation between the cool spot effect and the length of green canopies, wind speed, the ground surface temperature and eddy diffusivity were examined. Finally a simple model was proposed to predict the cool spot effect.
