I'm northeast of the Northeast, in Canada. Leaves are still on the trees (lots of trees near the pool as you can see in my profile picture) and we were swimming last night, and are expecting 80-degree F weather on Thursday.
I would suggest that it's time to cut down that tree!
This time of year we keep the solar bubble cover on when we are not using the pool, and especially overnight, both to keep in the heat and to keep leaves out. Swimming starts to get expensive as we use the propane heater more, but we usually find it's worth heating it in September, at least on nice days and weekends, but not so much in October,. As with @cowboycasey
, we don't close until the water is below 60 F, and never before Canadian Thanksgiving (2nd Monday in October), although swimming days in October are generally few and far between. We open the pool and balance the water as soon as the ice melts in the pool, generally around April 15, although we usually don't heat and swim before Victoria Day (the last Monday preceding May 25) weekend. Closing late and opening early both avoids a green pool and gives us time to balance the water in the spring and resolve any equipment issues before the pool stores get busy. If the temperature is forecast to dip below freezing we keep the pump running. We take the pump inside the house when we close.
Our CYA always reduces over winter, so we will soon be reducing daily maintenance by using less liquid chlorine and loading up the puck feeder to finish out the season. We also use it in the spring to replenish our CYA, and leave it empty in the summer.