When would you roughy ovulate with a 38-40 day cycle

[Mamabear2020x]

Any help much appreciated! :)
I think having sex on cycle day 20 onwards would be best chance ?

Luteal phase is usually between 11-17 days, so yes day 20 on probably.

If you chart your temperature on waking for a month you should see it rise after ovulation - then you'll know when it is.