The U.S. has reached another potential turning point in the pandemic. But this is also a moment when the Covid-19 data is unusually tricky to read. In today’s newsletter, I’ll try to make sense of it, with help from four charts created by my colleague Ashley Wu.

On the one hand, the country may be on the verge of a virtuous cycle of declining cases. Although scientists don’t understand why, Covid has often followed a two-month cycle: When cases begin rising in a country, they often do so for about two months, before starting to decline. In the U.S., the Delta wave began in early July, a bit more than two months ago.

On the other hand, schools across the country have recently reopened, and some other activities — like crowded college football games and Broadway plays — have restarted. All this socializing has led some epidemiologists to predict that cases could surge this month.

Right now, it is hard to figure out what’s happening from the much-watched charts that track daily Covid cases. Those charts have recently been messy because of Labor Day. With testing centers and laboratories closed for the holiday weekend, cases plunged artificially during the long weekend, before surging — also artificially — in the days after. As a result, the seven-day average of Covid cases (the measure that many trackers highlight) has been distorted for much of this month.