Cooling pool

Here we are in the middle of October and still swimming in the pool at least twice a day, at night the air certainly is a lot cooler and this is cooling the water a bit, but because we have a solar cover on the pool, the sun in the day is warming the pool water up to a certain extent I do think we are also aclimatising to the water temperature as it must be dropping slightly all the time now, the question is how long will it be before we find it just too chilly to be enjoyable.