Get relief from the heat at a Park District cooling center, or at a beach, pool, water playground or water feature. View sites & hours. Outdoor pools open for the season June 21. Due to the heat, previously scheduled swim sessions will be changed to Open Swims at outdoor & indoor pools, from 1pm until the scheduled pool closing time, on Saturday, June 21 & Sunday, June 22. For information on other City of Chicago cooling centers visit 311.chicago.gov. or call 311.