I'm not that experienced when it comes to flying these things with non-whirly wings, but I have been flying the C152/150 for...too long.
I was always taught to rotate at 60 kts, but keep in ground effect until you reach 70 kts, then start to climb. Of course, if you have flaps for a short fiield take-off, it will take off at a lower speed. I would always tend to let the aircraft take off when it wants to anyway, ie don't hold it down, but make sure you stay in ground effect until the speed reaches 70 kts. I suspect, Mazzy, that you were taught to not take-off before 70 kts for safety - beginners aren't always that good at keeping in ground effect.
most of my flying has been done in the colder winter months but the effects of that are probably quite negligible.
Actually, no, even quite small changes in temperature make quite a lot of difference to performance. You'll find out when summer comes - if it ever does.
But to repeat, I'm a helicopter instructor, and only a fairly low hours PPL(A), so don't take any of what I say as gospel.
Actually, you don't want to take what I say about rotary flying as gospel either, but I'm supposed to know about that.
