In Florida, with the Temperature and humidity in the 90s, a clapped out 150 and two fat gits on board, the aircraft will only reach 1000ft at the end of the downwind leg, given that the turn to crosswind is made at 500ft, the airport would be pretty well out of site if the turn to downwind was made only at 1000ft agl. Cessna 150s become hedge trimmers in high temperature and humidity conditions.