Actually I kept it open the first winter. Not a problem weather wise (esp with auto freeze protect), but it was more work scooping out old leaves, running the cleaner, adding bleach weekly, paying an extra $20-$30/month to run the pump, etc. So its closed right now - recently made a post in the Pool Opening forum on how deep I need to measure to get the correct pool temp so I know when to open. 6" down its in the low 50s. I'd prefer to leave it closed as long as possible with all the pollen. Plus like you, I don't start using it until early May.