When it comes to deciding whether to leave your dog in a hot car, the rule couldn’t be simpler: Do not do it—even for a few minutes, even on a mild day. Discerning if it’s too hot to walk your dog, on the other hand, is more of a judgment call.

Fortunately, there’s an easy way to make that call. Place the back of your hand on the sidewalk, pavement, or whatever other outdoor surface your dog would walk on. If it’s too hot to comfortably keep your hand there for about five seconds, keep your dog’s paws off it. As you might already know from treading barefoot on sand or asphalt, surfaces can be much hotter than the surrounding air; according to Lifehacker, asphalt on a 77°F day may reach a blistering 125°F. In other words, you should still use the 5-second rule before walking your dog in breezy, temperate weather.

Even if the pavement passes the test, it’s important to keep your dog cool during your stroll. Veterinarian Elizabeth Racine recommends sticking to shady areas, or finding a path along a lake or creek so your pet can splash around in the water. Speaking of water, carry some with you and give your dog plenty of drink breaks. And whenever possible, schedule walks early or late in the day, when the heat is less intense.

You should also monitor your dog for signs of heatstroke. Unlike humans, dogs don’t have sweat glands all over their bodies, and their main way to cool off is by panting. If you notice your dog panting heavily—or generally acting lethargic or fatigued—relocate to an air-conditioned spot post-haste. Heatstroke can quickly become fatal for dogs, so you don’t want to ignore the early signs.

If you decide it’s way too sweltering to walk your dog outdoors at all, they can still get some exercise indoors. Pet food provider Scrumbles suggests playing hide-and-seek around the house, running up and down the stairs with them (or tossing a ball to the top, if you can’t or don’t want to run the stairs yourself), or starting a tug-of-war.

A version of this story originally ran in 2021; it has been updated for 2023.

This article was originally published on www.mentalfloss.com as The 5-Second Rule: The Simple Way for Knowing When It’s Too Hot to Walk Your Dog.