Your pre-AI-Overviews baseline is already gone
The advice has been circulating since early 2026: export your Search Console history now, before your pre-AI-Overviews baseline falls off the 16-month cliff. It was good advice. In July 2026 it is also about a year late.
AI Overviews reached US search results in May 2024. Search Console keeps 16 months. May 2024 left the window around September 2025, and the cleaner baseline people actually wanted, late 2023 through early 2024, expired months before that. Open Search Console today and your oldest row is from roughly March 2025, which is ten months after AI Overviews were already sitting above the blue links.
So the before-and-after comparison isn't hard to run now. It's impossible to run. If you exported CSVs at the time, those files are the only copy that exists. If you didn't, no product can get that data back, including this one.
What's actually still in the window
A more useful question in July 2026: which comparisons remain possible, and for how long?
| Baseline you might want | Last clean month | Leaves Search Console |
|---|---|---|
| Before AI Overviews (US, May 2024) | April 2024 | Gone since around August 2025 |
| Before AI Mode's general release (May 2025) | April 2025 | During August 2026 |
| Before the September 2025 impression change | August 2025 | During December 2026 |
The middle row is the one to act on. AI Mode went generally available in the US at I/O in May 2025, after a couple of months in Labs, so April 2025 is the last full month describing your site before AI Mode existed for most searchers. Those rows start dropping out in about five weeks.
The third row matters for a quieter reason. Google changed how it counts impressions in September 2025, so impression numbers from either side of that date don't measure quite the same thing. Once August 2025 leaves the window in December, every impression figure you can still see will be post-change, and the discontinuity stops being visible rather than getting resolved.
The pattern is worth more than the deadline
Every row in that table was a deadline somebody posted about at the time. Each one passed while people meant to get around to exporting. The cliff isn't an event you can react to, it's a schedule, and manual exports lose to schedules. The March 2026 round of "export your historical data immediately" was entirely correct and still didn't help most people who read it, beacuse exporting is a task, and tasks compete with other tasks.
Whatever the next shift in AI search turns out to be, the baseline you'll want for measuring it is being recorded right now and will be deleted 16 months from now. That isn't a forecast. It's the retention policy.
What's left to do about it
Everything from roughly March 2025 onward is still in the window, which means it can still be copied. An archive started today captures the remaning window in a backfill and then keeps every day after it, which makes August and December stop being deadlines. That's the whole product: Month17 copies each property daily and keeps the rows with no retention limit, queryable from Claude or Cursor over MCP.
If you want the specific dates for your own property rather than the genral shape, the data loss calculator gives you them, and the 16-month write-up covers what the limit breaks beyond AI baselines.
The pre-AI-Overviews numbers are gone. The pre-AI-Mode numbers are going next month. The choice availabe today is only about which of those sentences you'll be reading again in 2028.