Warm weather will be moving into the upper Midwest by Friday. Seventies will be the norm for highs for the foreseeable future. Long term temperatures according to my favorite weather forecaster, has upper eighties possibly for Memorial Day weekend.
It looks like spring will come roaring back. For farmers and gardeners the warm weather will bring planting and new growth coming up through the soil. For beekeepers, LOOK OUT overwintered colonies will be swarming.
For overwintered colonies divides should be happening if you have eight frames of brood and bees.
Also, Mites are also a concern on overwintered colonies. Mite checks should be done NOW, on all overwintered colonies. Mites counts will start creeping as we move towards June. Failure to check or treat for mites soon, may result in your hive going south by July.
If you want to treat for mites right now, it is a good time for Formic Acid. If the formic can be put on soon, before it gets too warm. Using MiteAway quick strips would work well on strong colonies. The treatment period for Miteaway is seven days. Formic Pro, the treatment schedule is two weeks. With the Miteaway, the hive could be treated and a divide done right after the treatment is done. But swarm control should be in effect on all strong colonies.
The fruit bloom has slowed down with the of cold weather that we have been experiencing. New colonies have also been slowed because of the cold. Bees have been having a hard time expanding their brood nests. But now with the warmer weather, new colonies should pick up the pace of their spring development. With the warmer weather, nectar and pollen should be coming into the hive at a much greater rate.
Watch your hive population, keep up swarm control, watch the mite count, divide as needed. The cold weather is in the rear view mirror now, moving forward with a big colony, the main nectar flow is a little over a month away.