The honey flow has started in central Wisconsin. But don't let up on your every other week inspections of your hives. Overwintered hives should be putting honey into the honey supers. New package hives are still building their populations. It takes a full two months after package installation for the bee population to reach a point where the package will be large enough to bring in surplus nectar.
Another thing to be on the outlook for is American Foul Brood. The Natures Nectar blogsite is reporting a few instances of infected hives in Minnesota. Follow this link to read about it.