I have a 9 yr old son and it is all out war when we leave the house cause he wears t shirts year round (but so do I) and then he wants to go out with just a hoodie and a wind breaker .... So I have told him that if its minus 10 or colder he has to wear his winter jacket and -9 or warmer and he can wear his hoodie/wind breaker.... Thankfully it has been frigid for most of the winter so its been a non issue.