Sounds like the OP is happy but as a long time sufferer I'll add my 2 cents.
I think reverse draft and sluggish draft are sometimes used interchangeably but are from different sources which may both contribute to varying degrees depending on conditions and setup. Warm weather certainly can result in sluggish draft in an otherwise normally well behaved stove or fireplace due to lack of a pronounced temp differential.
Reverse draft, resulting from stack effects is a different animal altogether and often is often more pronounced and harder to overcome as it gets colder. Heat loss causing volumes of air to escape through the top of a structure needs to be replaced and often finds that the path of least resistance is through the chimney. This can result in flow that can be very strong. Under the right (wrong
) conditions the air rushing down the flue when I open the door of my insert can eaily be felt on the back of my hand and con even move ash in the insert. It usually gets worse as it gets colder although atmospheric conditions also seem to play a role.
I once had a full on reversal meaning the air feeding the fire to support combustion was coming from the flue. This was a scary situation which clearly showed me how little rope gaskets do when really pressed into service.
The draft doesn't care which direction it goes in but temp differentials between the envelope of the structure and the outside are the drivers. If your stove is below the neutral pressure plane like mine you know what I mean.