Why the 12th?
Most summer pools close the weekend after Labor Day. Declining use, shorter days, and the cost of heating the water is part of the reason. The biggest factor is a declining work force. Most of our experienced lifeguards have already left for college and as we begin the high school year, more and more staff members become unavailable with sports and other activities. Our large pool takes more guards than most facilities.
Why no parties the last week?
This is also because of a dwindling staff. We still have very competent guards, but many are beginners. Towards the end of August we've had days where there are almost as many guests as members using the pool. We simply want to make sure that we don't have a huge crowd during the last week.
Why are the hours 4:00 pm to 7:00 pm.
It turns out that state law limits high school workers to 4 hours a day. In the spring I have college students who can arrive a bit early to get the pool ready and stay as swimmers leave the facilty. This time of the year we schedule for three hours to make sure the staff member's total hours don't exceed the maximum.