Young son, it argues a distempered head

So soon to bid good morrow to thy bed.

The prefix "dis" means "not." Based on this, what is the most likely meaning of the word distempered?

Distempered could mean not angry or irritable. However, it could also refer to a not normal temperature as having a fever, such as distemper. Overall, the word could properly mean that the one referred to as "distempered head" is too weak to argue or resist.