Does a person's being struck by hail (small ice cubes accompanying rain) harm him or indicate Allah's wrath upon him?

Whether hail falling on a person's head is harmful or not depends on experience and medicine, and there is no evidence that it indicates Allah's wrath. As for rain, it is goodness, blessing, and mercy. Scholars have deemed it commendable for a person to uncover their head and part of their body when rain falls, based on the Hadith (definition) of Anas (may Allah be pleased with him): "It is fresh from its Lord," meaning that the rain is a mercy recently created by Allah Almighty, so one seeks blessings from it.