One thing is certain: Sitting in the sun does not change the colour of any (young) person's hair. Wearing a hat against the sun is a comparatively recent invention, necessary to protect one's (light-coloured) skin. This is true in Antigua and elsewhere.

However, many people change the colour of their hair by chemicals, for reasons of beauty. If the eye of the beholder has a different view, they might blame the sun, as a lame excuse.

But the Antiguan lyrics say "yuh", not "I", and "Dat's why yuh head so red!", not "Dat's why yuh head so red???".

I'm still puzzled, and so seem the natives.