If I had high temps for 3 days and then a complete dry up, I would consider myself safe. Be very, very careful, though before ovulation. I've read that sperm can only live 3 days, but they lived 5 in my case. Next time (and we will use NFP next time, this sweet baby was my fault, not the NFPs) I'll not be able to be unprotected before O at all, as I ovulate early in my cycle.
As for temping. It's really helpful to temp. You could just start temping at the same time (approximately) every morning, and then chart it and look for patterns from month to month. I think you really need about 6 months of charting to really see what's happening.