A few sightings of this phenomenon have been noticed starting as far back as two weeks ago. No, you don’t need it to be cold but darkness and clear sky are essential. See some of my old advice to those seeking to see Aurora, including a link to the local Kandalaksha group of Aurora hunters.
It started three weeks ago. Take a look at
https://www.facebook.com/alexandra.goryashko/posts/1786572324752299?__tn__=-R
https://www.facebook.com/photo.php?fbid=1786835018059363&set=a.344428978966648&type=3&theater
Towards the end of August? Pretty early! I didn’t expect it to start in August and wasn’t watching for Aurora-related news..