HN definitely has an older crowd, but additionally I've noticed HN is increasingly dominated by Europeans from 5am-2pm PST. "American" HN seems to kick off around 3pm-10pm PST now.

Even the HN dataset on HuggingFace shows that most engagement on HN is now during non-US hours [0] and drops off as Europe goes to sleep.

[0] - https://huggingface.co/datasets/open-index/hacker-news