Are these size variations normal?

For me, the length of my flaccid and erect varies. Normally my unerect is about 3" long. However, whenever it gets cold or chilly outside, or if I'm sick, then it can sometimes get shorter than 2"! Same for erect. If I'm just doing a casual, non-masturbatory stroking of my shaft, then it's about 5.5" long. But when I engage in full on head and shaft masturbation, it maxes out at around 6.25" (by the way, that's considered quite normal right? 6.25"?). Does every man have these kinds of variations or is it just me?