He has since he was a baby. One of his first memories is climbing into his mom’s bed in the middle of the night while thunder shook the sky apart and lightning framed the curtains in his bedroom. He remembers the creak of his mom’s bedroom door, her sleep soft voice full of concern, the warmth of the covers as she wrapped him up next to her.
It’s almost twenty years later and he’s still left trembling at the first flash of lightning. He knows now, logically, the reason behind this. He has stood in front of a god who has threatened to blow him out of the sky, who has held the physical impossibility of a physical lightning bolt in his hand and wielded it towards Percy. He knows that not every thunderstorm is a threat to his life. He knows, he understands, he fucking gets it.