Pools typically open when the weather becomes consistently warm, generally when daytime temperatures are above 70 degrees Fahrenheit. Opening earlier can help avoid algae growth and excessive pollen buildup in the water, making maintenance easier. This is often in spring, around April in many regions, but it depends on local climate conditions.
For public outdoor pools like those in New York City, the pools are open daily during the summer season, usually starting in late May or early June, with hours from 11 a.m. to 7 p.m. and sometimes extending to 8 p.m. during heat advisories. In Toronto, outdoor pools open daily from 10 a.m. to 8 p.m. through the summer and usually close by the end of August or early September.
So, the best time to open or use pools depends on your location and weather, but typically pools open in late spring or early summer when temperatures stay comfortably warm.