Yes, if you do a web search on a monthly climate chart for Warsaw, you will see that August, and even the beginning of September, are still quite warm, though by no means is it a balmy region. So a reversible parka would not fit in with this time frame.
Interesting youtube video - a little before the halfway mark looks to be footage from the tank battle. Gives a good idea of the topography.
Photo set of reenactors doing Wolomin 1944.
Another googled photo, captioned:
SS man walk past a burning T-34 tank in Poland. Near Warsaw. August 1944.
regards,
Jack