I live in Eastern Canada, where the temperatures are currently 57 at night and 72 in the day. I keep the pool at 78 until the weather warms up. This might seem cool to those in the south, but you get used to it, particularly with the cost of propane (no natural gas) here! When the pool water gets to 84 in mid-summer, I leave the solar cover off at night to let it cool down, as we find the water too warm to be refreshing! Our "perfect" water temperature is 81.