Mine have been either a week or two before a race I wanted to do well at, or after. Couldn’t wring one out on race day. I suppose this is a question of Knowing Thyself. So, how do you know yourself? I don’t know that peaking is the right word for it–maybe I consider “peaking” to be what top athletes do with periodization. I am thinking more of AG’ers who still have lots of room for improvement year to year–“plateauing” may be a better word, followed by a drop off after the gain.
I had a PB at a local tri last year. I only knew it when reading the results after the race. Never would have suspected.
Too many factors on race day such as winds, temp., your constitution, etc to predict in advance.