Peel back the husks of each ear of corn, leaving them attached at the bottom. Remove the corn silk strings around the kernels. Return the husks back around the corn. Soak corn in a bowl of lukewarm water for 1 hour.
Preheat an outdoor grill for medium-high heat and lightly oil the grate.
Mix salt and lime zest together in a bowl.
Remove corn from water and peel back husks, keeping them attached at the bottom. Pat corn dry using paper towels, leaving the husks wet. Brush the corn with melted butter and sprinkle lime salt and chili powder over the entire surface of each cob of corn.
Cook corn on the preheated grill, turning occasionally, until tender, about 25 minutes.