I was looking at the Realclearpolitics rolling average of polling in battleground states. I looked at this day in history for 2016, 2020 and today. Still lots of time left until election day but it's pretty interesting data.
Arizona
2016: Clinton +1
2020: Biden +4
2024: Trump +4.8
Wisconsin
2016: Clinton +11
2020: Biden +7
2024: Trump +0.3
Michigan
2016: Clinton +8.3
2020: Biden +8.6
2024: Trump +0.2
Pennsylvania
2016: Clinton +0.5
2020: Biden +6.6
2024: Trump +2.3
North Carolina
2016: Trump +3
2020: Biden +0.3
2024: Trump +5.3
Arizona
2016: Clinton +1
2020: Biden +4
2024: Trump +4.8
Wisconsin
2016: Clinton +11
2020: Biden +7
2024: Trump +0.3
Michigan
2016: Clinton +8.3
2020: Biden +8.6
2024: Trump +0.2
Pennsylvania
2016: Clinton +0.5
2020: Biden +6.6
2024: Trump +2.3
North Carolina
2016: Trump +3
2020: Biden +0.3
2024: Trump +5.3