What’s the best time of year to close your pool?

[Mark Davis]

I’ve seen some people close up right after Labor Day and others wait until October. Is there an ideal time based on temperature or water conditions? I don’t want to do it too early and end up with green water in the spring. Just curious what’s worked best for everyone.

 

[John Miller]

I always wait until the water temp drops below 60°F. That’s the sweet spot because algae can’t really grow at that point, and your chemicals will last through the winter. If you close too early while the water’s still warm, you risk opening up to a cloudy green mess. So I usually aim for late September or early October, depending on the weather.

 

[Oscar Ricci]

I also wait until the water temp drops below 60°F. At that point algae can’t really grow and the chemicals last longer through winter. I usually close my pool in late September or early October, depending on the weather.

 

[Ionut Kaminski]

I usually go by water temp, not the calendar. My rule is: close when the water is below about 60°F (15–16°C) and the water is still clear. If you close too early while it’s still warm, you’re more likely to open to cloudy or green water.

 

[Amira Mansor]

For me, I go by water temp, not the calendar. I usually close once the water is below about 60°F (around 15–16°C) and the water is still clear. If you close too early while the water is still warm, I have seen pools open up cloudy or green way more often.

 

[Diego Rodriguez]

What has worked best for me is waiting until the water is consistently around 60°F or lower because algae slows way down at that point, closing too early while it is still warm is usually what causes green water in spring, and once I hit that temp I close and add aquadoc pool closer winterizing kit so the water stays stable all winter.

 

[Lily Allen]

The ideal time to close your pool usually depends on the water temperature and local weather. Generally, when the water temperature drops below 65°F (18°C), it’s a good time to close the pool. I typically wait until the water is cold enough to prevent bacteria and algae growth, and I use AquaDoc Pool Closer/ Winterizing Kits to keep the pool protected during the winter without algae or buildup issues.

 

[Brandon Hayes]

I’m in the “watch the water, not the calendar” camp, but one thing I’d add that hasn’t really been mentioned is consistency.

A single cold night doesn’t mean it’s time to close. I’ve made that mistake before. The water dipped under 60°F for a day, I rushed to close, then we had a warm stretch and the water sat in the mid-60s under the cover for weeks. That’s the only year I opened to early algae even though I thought I’d done everything right.

What’s worked best for me is waiting until the water is staying around 60°F or lower for several days in a row and the forecast looks like fall is actually settling in. At that point algae growth really slows down and whatever sanitizer you leave behind isn’t fighting an uphill battle.

I also make sure the pool is as clean as possible right before closing. Brushed, vacuumed, no visible debris. Closing a week later with clean, cold water has always been easier on spring opening than closing early with warm water, even if it means swimming one less weekend.

So late September to October ends up being right for a lot of people, but the real trigger is stable water temps, not a date on the calendar.

 

[Alma Weber]

I always wait until the water temp drops below 60°F. That’s the sweet spot because algae can’t really grow at that point, and your chemicals will last through the winter. If you close too early while the water’s still warm, you risk opening up to a cloudy green mess. So I usually aim for late September or early October, depending on the weather.

From what John Miller and the others mentioned about the 60F mark, that’s the rule I follow every year. One time I closed too early while the water was still warm, and even though I shocked it, I opened to slightly green water because phosphates had time to do their thing before it got cold enough. Since then I wait until it’s consistently below 60F and make sure the pH is stable before covering. For me, water temperature matters way more than the calendar date.