If you are looking to get retweeted and nobody picks your tweet up within the first hour, chances are that nobody ever will. Only 1.63% of all retweets happen in the second hour and a minuscule 0.94% in the third hour. The same is true for @replies, too; 97% of all replies happen within the first hour.
I can attest to this. The things I’ve made that have BLOWN up have ignited within the first couple minutes. Very few delayed reactions. Either it sings, or it doesn’t.