The high water temperature during the summer months can make water activities more enjoyable, but it can also lead to an increase in algae growth, which can affect the lake's water quality. Regular monitoring by the Arizona Game and Fish Department and the Tonto National Forest Service helps ensure that the lake remains safe for recreational use. In the fall, the water temperature begins to cool down again, dropping back into the 70s Fahrenheit (around 25 Celsius) by October and back into the 50s Fahrenheit (around 10 Celsius) by December. This cooler water temperature can lead to a decrease in algae growth and an increase in water clarity. In the fall, the water temperature begins to cool down again, dropping back into the 70s Fahrenheit (around 25 Celsius) by October and back into the 50s Fahrenheit (around 10 Celsius) by December. This cooler water temperature can lead to a decrease in algae growth and an increase in water clarity.