Gallup’s Jeffrey Jones talks about the implications of this for November:
A stronger-than-usual anti-incumbent bias is another challenge for a majority Democratic Party that is trying to minimize the losses usually dealt to the president’s party in a midterm election year. Gallup’s Daily tracking of registered-voter candidate preferences this year has typically shown Republicans and Democrats tied or the Republicans with a slight lead, either of which would generally predict a strong Republican showing at the polls on Election Day.
That day is still nearly five months away, but typically, voters’ attitudes toward incumbents do not change dramatically over the course of an election year. To the extent change has occurred in a given election year, it has usually been toward a more negative rather than a more positive view of incumbents.