A man suffered two fractures to his skull when he was punched to the ground by snowball-throwing yobs after asking them to stop.
The 31-year-old asked the teenage gang not to throw snowballs at his window, but they then set upon him on Sunday just before 1800 GMT.
The attack happened outside Purbrook Chase Precinct, Waterlooville.
The victim was taken to the Queen Alexandra Hospital, Portsmouth, where he received treatment.
Police are appealing for witnesses.
Det Con Emma Cooke, of Hampshire police, said: "This was a vicious attack which left the victim with two fractures to his skull.
"At this stage we believe three youths were responsible for the assault."