CNET looked at Apple’s track record over the past few years to pick the most likely date for the new iPhone announcement and came up with Wednesday, September 12th. That takes into account the days of the week and time in September Apple usually chooses for its iPhone events. Next, they looked at prior announcement proximity to Labor Day. They say,
For the last six years, Apple held its iPhone announcements on either a Tuesday or Wednesday, and usually no later than the second full week of September…For 2018, Labor Day falls on Monday, September 3. So, if Apple follows its recent pattern, the company would announce its new iPhones the following Tuesday or Wednesday: September 11 and September 12.
Considering the negative connotations that go along with September 11th in the United States, that leaves the 12th. Since first deliveries follow about a week and a half later, that means we’ll have new iPhones in our hands on September 21st.