The AI Models Index keeps tabs on premium model releases from 15 top labs since...

https://sierra-wiki.win/index.php/Why_Are_Waitlists_and_Trusted_Tester_Programs_Excluded_from_Model_Release_Dates%3F

The AI Models Index keeps tabs on premium model releases from 15 top labs since 2023, verifying dates and using blind-vote checks for accuracy. Updated every two weeks, it shows release cadences improving — like GPT-5.2 launching just 4.5 days after GPT-5