Lou, To answer your questions: cold/climate problems=yes, goofy contractor=usually. It isn't all that uncommon to pour it later. Up there in Minnesota 4 things come to mind, 1. tract housing where the framing subcontractor got there before the concrete subcontractor, 2. Waited to cover it, not only for the weather but to heat the grade and the concrete while it is setting up (you can't pour on frozen ground and you need to cover it to avoid letting new concrete freeze) 3. they just haven't gotten to it yet with the framing more important depending upon the weather 4. Waiting on the plumbers, etc.