I think I can do this…

Gluttony is January because we all eat and drink too much to celebrate New Year.

Sloth is March because of springtime lethargy.

Envy is July because adults are envious of kids who get to enjoy summer vacation.

Wrath is November because of all the fights during Thanksgiving dinner.

P. S. This comic was inspired by a comment I got during a previous Pride Month. Thank you.