Turning red describes something that is changing to a red color. It often means a face flushing from embarrassment, anger, or effort. It can also be literal, like leaves in fall or a warning light.
my mother was taught the ch'an concept of happiness, which was to find satisfaction in small things. i was taught to appreciate the fresh air in the morning, the colour of leaves turning red in autumn and the water's smoothness when i soaked my hands in the basin. Anchee Min