Our flow season is about one month long. There is a flow often at the beginning of June but seldom hives are ready to forage surpluss.
After September we go to the winter. When the hive makes brood in September, it makes sometimes tight that the last emerged bees can empty their gut.
Our plants start to prepare themselves for winter in August what ever weather it is. Plants read the time from day lenght.
Finski, I think I see the source of confusion. David's in Pennsylvania, about the same latitude as I am. (you're at LOWEST 60N he's between 39 and 42N, BIG difference!) We get a fall flow in August, usually goldenrod mostly but also fall raspberries and other wildflowers. Depending on the weather, bees can pack quite a bit in during that month.