Cooling at an idle

[tdangle]

Yesterday it was 96 outside. Waiting in line at a restaurant I noticed my temp slowly climb to the top 2/3 of the normal operating range. Of course I had the A/C running. As soon as I hit the road, within a long block it was back down to the bottom 1/3 of normal range. I had an 88 1 ton with a mechanical fan and a small pusher electric fan. Wondering about picking up a pusher fan for my truck and wiring it so it comes on with the A/C. Didn't overheat, I just like to see the temp gauge not move at all from normal. Pros/Cons??