All agreed JD.My experience of F2 on say 20m (from a half decent location)
has always shown that the band can be open pretty much 24 hours a day
(subject to seasonal and solar activity).
Sporadic E can be 24 hours too, or small openings can occur at any time
at all.
I did a long term observation of 10m band G signals to southern Spain last year
and wrote up my findings in 74! Compendium here -
https://qsl.net/g0ftd/other/misc/74%20-%20Knights%20QRSS%20Winter%20Compendium%202021.pdf
This year's season appears to have started late.
Normally I observe the season starting to open in the second week of May,
but this year the door started to open, but not very far.
Only in the last few days does it appear to be starting (assuming it's not
a false start).
74 de Andy