Yeah I know.
As for the weather either way someone looks stupid.
If its warm won't Dante and Vergil seem like they're over dressing and both are wearing a large excessive amounts of black (especially Dante) so they should be attracting a lot of heat and be burning up in all that clothing (especially Vergil). Then again why is Kay wearing a sweater unless she wants to..........sweat more.
If its cold out....put on some damn pants....although I know schools who allow girls to wear skirts during the winter...even if they're wearing stockings it must be very uncomfortable.
As for the weather it might be spring where both are fine or the usual answer most writings take in "What weather?" and just leave it ambigious because unless there is a reason why the weather (or time) actually mattered to the plot there is no reason to be specific about the weather.