Essentially a London Fog is a type of tea latte. Of course, there are lattes made with coffee instead of tea which differ from both a tea latte and a London Fog. When we talk about a London Fog, we are specifically referring to a latte made with earl grey tea. However, all lattes (and thus, a London Fog) all have at least one thing in common: that delicious steamed frothy, foamy milk on top! Therefore, the difference lies in the base (the kind of coffee or tea) used to make it.