The colony is now at or near its peak population. You will probably notice bees bearding up on the front entrance of the hive in the evenings. This is simply the bee's way of cooling the hive on these hot summer days. However, too many bees may be an indication of poor ventilation or a lack of room in the hive. If needed, add a super (there is still time to fill it up) or give more ventilation by propping the cover up about a 1/4".
Add supers as needed but keep in mind that harvest time is fast approaching. If needed, harvest full supers now to make room. Use shallow or medium supers instead of deep or provide the supers with drawn-out foundation.
The mite population will also be booming at this time (in 2nd-year colonies) so don't forget to check mite counts and be prepared to treat AFTER the honey comes off.
Be prepared for harvest time next month; order bottles & caps, buckets and whatever else you may need for the harvest season. You don't want to wait until last minute and have full supers setting around with nowhere to put the honey.
Watch for robbing activity from other bees or wasps. The end of summer is when other, stronger hives or wasps/hornets will attempt to steal honey from weaker hives. If necessary, reduce the entrance of the hive being robbed to help them defend the hive more easily.
This is the month when the winter bees are being laid; near the end of the month. Ensure a strong winter colony by checking the food stores starting at the end of this month; there should be plenty of food in the brood boxes. Remember that a strong hive going into winter with plenty of food will ensure a strong hive coming out in the spring and that means more honey next year.
Now is the time to ensure that your bees will have enough room to last the summer but not so much that they can't fill the supers before harvest time. Follow the rule of 7/10; if 7 of the 10 frames are fully capped, add another super (early in the month). If it is later in the month, leave them be as they can begin to fill the bottom brood chambers with winter stores.