kduffyvt09

I am trying to jump start a subaru impreza with a 2015 kia optima. The subaru has been sitting for at least a month or so. Ive had the cars connected for at least a half an hour now and still can't get the subaru to turn over. It is only about 30 degrees out but Ive been able to get it charged enough to put the heat on and get all of the dashboard lights on but it still wont start. Any help would be greatly appreciated.