As with many things in beeking, it will depend on location weather, and pollen and nectar flows and times.
Here where I'm at, I get good strong flows from mid to end February through end of March, slows some in April, picks up strong in May for blackberries, slows in June, picks up end of June thru end of July for starthistle and black locust. After first of August, I get no flows.
The hives will be packed with pollen on August 1, but it will all be gone September 1. I find in my area, it's very important to supplement pollen and feed sugar water in abundance from end of August when I pull honey, through the middle of October. By middle October I stop the sugar water and will cut back and stop the pollen by November 1.
This will get them built up with younger bees and full of cured stores before weather turns cooler and moister in November. It will give them stores of pollen for brood rearing to start up again in middle January to tide them through until middle February when pollen once again starts coming in.