The property management companies here in Longmont are under siege. Vacancy rate has been reported at 3 percent. However, I suspect it is less than that - judging by all the tearful calls we get here at PML.
The closer you are to Boulder, the more that vacancy rate drops.
If you're calling for rentals in many metro areas, I suspect this is the case.
More apartments are coming on line, though. So, keep trying.