Please remember that you may not see a lot of difference in the model as the weather changes but it can make a HUGE difference in a full scale operating in mountainous areas in the summer...
or when taking off from an extremely short, muddy field on an oppressively hot and humid day in an old 1850 SMOH Cessna 140 with your overweight girlfriend full of fried chicken, potato salad, bisquits and apple pie ala mode with huge pine trees to clear at the end of the runway[X(]