Summer weather’s effects on pools

Sunny. 90 degrees. It’s the type of weather that sends many people to the swimming pool but can also be the most challenging to keep the pool’s water quality at proper levels.

Large, small, private or municipal – weather affects all outdoor pools in a few ways.

Cloudy or algae-covered water isn’t safe to swim in, not that you’d probably want to, anyway. Chemicals such as chlorine and muriatic acid help keep the pH levels in the right spot. 

Heat and sunlight

Warm temperatures and sunshine try to undo that work, though.

As temperatures climb past 80 degrees, breaks down chlorine, according to New York City Parks. But it’s not just chlorinated pools that feel the heat.

Kate Carpenter, senior director of digital weather at Spectrum Networks – and self-described “pool whisperer” – notices the same thing with a saltwater pool. “Once the temperatures start to get into the 80s consistently, the pool tends to need a cup of muriatic acid once a week,” she adds.

Ultraviolet (UV) light from the sun also affects the chemicals in the water, especially near the surface.

Rain

A light shower passing over the pool is a drop in the bucket, so to speak. Those big summer downpours, that’s a different story, though.

A lot of rain can dilute the pool water, throwing off the pH levels.

Wind

The wind itself isn’t a problem, but the wind blowing around pollen and leaves is. They can strain the filtration system.

“When we have lots of pollen or leaves in the pool, we have to empty the skimmer multiple times a day and have to clean the filter at least once a week,” says Carpenter.

One other factor: busy days. When lots of people are hitting the pool, chemical levels in the water change, so a string of sunny and steamy days can become especially difficult for keeping pool levels in check.