when going to hot and humid Singapore. It is best to bring extra light colored t-shirts and athletic of jogging shorts rather than dark colored shirts or jeans as the dark colored shirts tend to absorb more heat rather than reflect the heat of the sun. Singapore is a tropical and humid country and it sits just accros the sea hence light colored t-shirts is best for reflecting part of the heat and humidity and having jeans add weight when walking for long stretches unlike wearing the lighter walking shorts or athletic shorts.
you will have to bring a change of clothes as you would sweat a lot while touring the Universal Studios and Sentosa Island. more so if you don;t take a bath everyday, specially for the white dudes.