In 2018, a Hawaii study found green roofs stayed cooler than white roofs in Honolulu

A University of Hawaii study found green roofs stayed cooler than white roofs. The green roof's average daytime surface temperature was 4.1°F lower. Peak temperatures on the green roof were 18.5°F lower than the white roof. Evapotranspiration from plants cooled the surrounding air significantly. This vegetation offers a method to combat urban heat island effects.