With the accurite that I have, it has a sensor on a long wire, for indoor and outdoor temps. You can put the wire in the bottom bin, and the unit in the top bin. Then the "outdoor" temp is the temp in the bottom bin, while the "indoor" temp is the temp in the upper bin.
The middle bins should be between the top and bottom readings. The top bins sometimes get warmer than the bottom ones, so it's important that you check all the bins as much as possible.