It sounds odd to have the staff perform maintenance work at the warmest temperature of the day, not to mention the period of time where the demand is also high.

It sounds odd to have the staff perform maintenance work at the warmest temperature of the day, not to mention the period of time where the demand is also high. Imagine a subway that is closed in the early afternoon for maintenance, people would be stranded and businesses would be outraged. Reading between the lines, the parks' real audience may be office workers who are employed during this time, and the parks are closed to keep everyone (undeserving) out so that they are nicer for those people. But I'm not part of this culture.