Though not universally true, a president's approval rating is likely to be highest when?

At the during their term following inauguration.

According to Gallup, The approval ratings for Presidents Truman through Obama were as follows:

1st term: 47%-74%

2nd term: 36%-60%

Approval ratings drop significantly from the 1st to 2nd terms.

A typical question asked to poll participants is "do you approve or disapprove with the way the President is handling his duties?"