You may have heard this poem in the past, and not known what it meant. Here is an entomological explanation. -Dr. Kathy
A swarm in May is worth a load of hay; a swarm in June is worth a silver spoon; but a swarm in July is not worth a fly.
This is a proverbial beekeepers' saying, mid-17th century; meaning that the later into the summer it is, the less time there will be for bees to collect nectar from flowers in blossom to make the honey the beekeeper wants and needs to make a living.
For instance, it is currently May, and my back yard hive queen bee is laying eggs right now (over a thousand a day) to build up the colony and make more foraging worker bees. These workers will go out and gather nectar. If I'm not cautious, and I don't get into my hive at least once every 10-14 days-depending on temperature- (the time it takes for a new queen to develop inside of what's called a swarm cell), then one day, I will find that the old queen has left with half of the workers, and a new queen has emerged in the hive to take over the other half of the workers remaining. This cuts down on my nectar-gathering work force severely (by about 50%!), and so I will ultimately have less honey and make less money if I’m a beekeeper who sells my honey. In May, the work force is building through the complete metamorphosis process; (all of the eggs develop into larvae and then pupae, and then they ultimately emerge as adult bees); this workforce peaks in June, timed when the nectar flow from blooming flowers is best; and then, the workforce drops as the drought begins with the heat in July and there are fewer flowers.
By the way, if a hive swarms and you find a swarm of bees hanging out on your balcony or eave or bench, do not treat them with a pesticide. Go to the local Beekeepers Association website for a list of beekeepers willing to collect swarms. This must be done the same day you see the swarm, before the scout bees find a permanent new location for the colony to move and live in.
Bee swarms, although scary looking perhaps, are very gentle. The bees are confused, not used to being out in the bright daylight, and just want to be near their queen who is in the center of the swarm for protection.