Will it damage the paint if........?

[t@#$%^&tttl_+t]

I'm going to spray paint the plastic on the interior of my car eg; the dash, speaker covers & other things. but i live in a town in Australia that get 40 degrees celcius heat during the summer(which isn't far away). if i paint it, will the paint crack or get damaged in the heat? im painting it black by the way. thanks in advance