"In some countries (eg, Ireland and Cyprus) the tradition goes that after 12 noon you can no longer play tricks. In the afternoon, whoever does play a trick becomes the fool. This scenario may have been designed by adults to give themselves a bit of a rest.
There is a rhyme that children recite if anyone attempts an April Fool trick after 1 April:
April Fool is dead and gone,
You're a fool to carry it on."
http://www.bbc.co.uk/dna/h2g2/A516791
I didn't find any other time limit rules in a quick internet search. Accordingly, only people from Ireland and Cyprus have the right to complain about it continuing past noon.