MidSummers eve is a big holiday in northern europe, being the longest day of the year. I think the longest day actually lasts about three days, somewhere around the 23rd or 25th of June. Amazingly enough, the year has now begun to wane. Imperceptible at first, but the sun begins to drop and the days become shorter. It is the time to plant seeds for winter veggies, autumn flowers, and so on.
Has anyone else seen a diminished rate of egg laying too? Compare the ratio of unsealed to sealed brood. A ratio of 1 : 2 indicates egg laying is steady, in other words if you have two frames open and four sealed, the queen is neither increasing egg laying or diminishing however if you have say 1 1/2 open and 5 sealed she is cutting back pretty good.
This is the time of year when the reproductive capacity of Varroa can begin to overwhelm the bee colony. Mites are accelerating while the bee is cutting back. If there is an appreciable population of Varroa soon all the bee larvae will be infested. The summer workers are tired and aged. Things begin to go to heck, if you know what I mean.
Monitor your mite levels ( you got 'em ) and try to knock em down by Aug. 1. After that you have app. 60 days to raise your Winter bees. How quickly pass the seasons and the years!