If we look at past Apple events in September and earlier iOS releases though, a pattern emerges to show we should expect Apple to release iOS 17 a few days after this year's September event.
 
I reached out to Apple about when it planned on holding its September event and when it was planning to release iOS 17. The company didn't respond, but here's when I think Apple will release iOS 17 based on what I see in my crystal ball.
When is Apple's September event?

Well, it's… in September. That's as much as we know right now. Apple is pretty good about keeping secrets, and it hasn't given a specific date for the event yet. But Bloomberg's tech reporter Mark Gurman expects the event to be held on either Sept. 12 or 13, and I trust Gurman.

What makes you think iOS 17 will come out shortly after the event?

Apple might be secretive, but it's also a little predictable.

For more than a decade, Apple has consistently held events every June and September. The company might have other special events in March (see 2022) or October (see 2021) but its June and September events happen every year like clockwork.

And after most of Apple's September events, the company released the next iOS within the following week. In 2018, for example, Apple's event was held on Sept. 12 (sound familiar?) and it released iOS 12 five days later on Sept. 17.

There have only been three years over the past decade where it took longer than a week for Apple to release the next iOS version -- 2019, 2014 and 2013. Even in those instances, Apple still released the next iOS version eight or nine days after its September event.

The number of days between Apple's September event and the release of the next iOS version has also trended downward over the past decade. In 2013, Apple released iOS 7 on Sept. 18, eight days after its Sept. 10 event, and last year Apple released iOS 16 on Sept. 12, five days after the company's Sept. 7 event.
What days of the week were past iOS versions released on?

All the iOS version updates were released during the week over the past decade. Apple released nine of the past 10 iOS versions between Monday and Wednesday and one iOS version on a Thursday. Apple hasn't released an iOS version on Friday, Saturday or Sunday over the past decade.

Wednesdays and Mondays are popular days for Apple to release iOS versions, with four iOS versions being released on a Wednesday and three versions on a Monday. Apple also released two iOS versions on Tuesday. So it's more likely that Apple will release iOS 17 on a Monday or Wednesday.

Look, just tell me when iOS 17 will be released

If Gurman is right and Apple's event is held on either Sept. 12 or 13, and Apple releases iOS 17 five or six days later, we get a timeframe of Sept. 17 to 19.
 
However, Apple historically doesn't release iOS updates during the weekend and Sept. 17 is a Sunday this year, so we can rule that day out. That gives us a potential iOS 17 release date of Sept. 18 or 19.

And since Apple has released past iOS versions on Monday more often than Tuesday, I'm predicting Apple will release iOS 17 on Monday, Sept. 18. You heard it here first.