Your water level is probably too low.

Cavitation happens when your pump is gasping for water—air bubbles forming and collapsing, eating away at the impeller. In hot weather, water evaporates faster, so the level in your pool drops, and the pump has to work harder to pull water through the skimmer. That increased suction loss is the setup for cavitation.

First thing: check your skimmer water level. If it’s below the middle of the skimmer opening, you’re pulling air. Top it off. Also make sure your pump strainer basket is clean and there are no debris blockages. If you have a variable-speed pump, dropping to a lower speed reduces the pressure differential and gives the water time to flow in properly.

If the level is fine and the basket is clean, check for a vacuum leak in the suction line—maybe a loose lid gasket or a cracked pipe. Hot weather can also cause pump seals to dry out and let air in.

Before you start diagnosing pump problems, top off your pool. Nine times out of ten, that’s all it takes. Your pump will thank you.