Winter does create very pleasing performance improvements. Certainly account must be made for the affects of a hot, humid day. The climb performance of a 150 with full flaps out is, as I have previously stated, pathetic. The requirement from the design standard is 1:30. That means that during flight testing in (or corrected for) a standard atmosphere, the 150 demonstrated a change in altitude in a mile of 5280/30=176 feet, or probably 176 feet per minute if you're doing at 60 MPH. If in doubt, go up high and try it. I would have, and reported back by now, but I'm working in Germany this week, and not near my plane.
Pilots of broadening flying skills need to get used to aircraft with non-stellar perfomance. Why? Once you are truly comfortable handling a plane with a best rate of climb of 176 feet per minute, you'll be ready for the single engined performance of some twins when heavy. Recent flight testing I did on a transport category twin, with externally mounted equipment and wheel skis, produced a negative rate of climb on one engine with 110% power on the other The aircraft did not pass. It would have been a bad day if we'd actually lost an engine after takeoff!
Don't knock poor performing aircraft, learn to deal with them the way the manufacturer intended (oh, I've just been told we're going to fly it again - see ya)
Pilot DAR