C-152 carb heat on before landing in hot weather?
You should always pull the carb heat when throttling back no matter the conditions for 3 reasons:


Ice forms from moisture (duh!), and there's much more moisture in hot tropical air than cold arctic air, so being in a tropical location does not lower the icing potential. The temperature drop is caused by the Venturi Effect which aerates the fuel in the carburetor, fuel is not frozen in the carb by the outside air temperature, you can get carb icing on a hot day
Habit: it's important to get into good carb heat habits, otherwise you may forget to pull the carb heat when you need it. Make it so automatic it just happens without conscious thought
Workload: Deciding when to use carb heat or not requires thought, you have to consider density altitude, temperature, relative humidity, the make of the carb, and other factors to make the right decision. Why add to your workload when 90% of the time you're probably going to conclude you do need it? Approach is a busy time, you should be spending time looking for traffic, maintaining airspeed and the other critical aspects of flight


It's worth reminding as well that icing can happen in cruise as well, so keep in the habit of applying carb heat regularly.