I've left boat for 2-3 months at a time in the Bahamas many times, when I come back, there is hardly if any growth, and if there is any, it comes off quickly and easily with a sponge, Scotchbrite pad or rag. I'm guessing the water temperatures were low to mid 80's. Recently, I've had the boat in New England, the bottom has to be cleaned once a month … minimum. And the cleaning not as easy as in the Bahamas. Summer water temperatures here I'm guessing very low 70's, maybe high 60's. Same condition and type of bottom paint. So, for me, water temperature is not the determining factor. More important than the temperature, I think are … the salinity of the water, how nutrient rich it is, how often the water is exchanged. Another reason why I love the Bahamas. Cheers, John