According to The New Republic (“liberals who can be reasoned with”), it’s 36 days:
“Humorous responses to Sandy’s destruction rose, peaked, and eventually fell over the course of 100 days,” wrote McGraw. “We find that temporal distance creates a comedic sweet spot. A tragic event is difficult to joke about at first, but the passage of time initially increases humor as the event becomes less threatening. Eventually, however, distance decreases humor by making the event seem completely benign.”
Before the hurricane hit, when the danger was still hypothetical, people thought the tweets were pretty funny: They gave them, on average, between 3 and 4 points on the 1 to 7 scale. But when Sandy arrived and people realized the extent of the damage it had wrought, humor declined, reaching a low point 15 days after Sandy’s landfall. As time passed, though, it became more and more acceptable to “find humor in the tragedy,” and people’s rankings climbed—reaching a peak 36 days after landfall. After this point, humor dropped off again, reaching a new low at Day 99.
It must be true, because there are graphs. Science!