With May temperatures rising slowly, it might not feel like the time of year when municipal pools re-open. But it is. With May temperatures rising slowly, it might not feel like the time of year when municipal pools re-open. But it is. Most of the pools will be ready for business today and will remain open through Labor Day, though Garfield Municipal Pool in Danville, which has an attached AMBUCS zero-depth spray park for kids, will close Aug.