I actually am not sure that this summer will be more violent in the US than last year, which was absolutely full of cultural and political stressors. The economy was massively shocked as the pandemic lockdowns caused people everywhere to modify their life, especially the lower class in dense urban environments. We had the most contentious election since the 1860's, which was prepended by country-wide riots and protests over police brutality and racial issues. Tribalism risked turning into sectarianism, and everyone I knew made plans in case widespread violence broke out.

Now, it's a completely different situation. The economy is swiftly recovering, and with so many people on unemployment still, the labor market is swiftly becoming tight, meaning lower class wages may spike soon. While the election was contentious, the leadership of the political parties have been focusing less on contentious social issues and more on infrastructure and fast economic recovery. The fringes of both parties have been tamped down. Masks and lockdowns are in the rear-view in most places, and everyone who wants a vaccine can get one(for the most part). I bet with this stability and increased hope will come a reduction in violence.

Have murders increased in other countries? That may hint whether it was caused by our unique stressors or if it was more generic.