Make sure you have the right shoes for the weather, too, Dr. Goldwaser said. When it’s raining, snowing or icy, you’ll want shoes with prominent tread on the bottom to ensure good traction. (That said, if it’s quite icy or snowy out, you may well want to stay home, Dr. Fleeter said.)

When exercising in low temperatures, continue to hydrate, even if you don’t feel thirsty, Dr. Fleeter said. When cold, the body releases a hormone called vasopressin that constricts blood vessels and also inhibits thirst, so you may not feel like you need to drink water even though you do, he explained. Also, when you exercise in the cold, your body burns extra calories to stay warm, so you may want to eat a bit more than usual to keep your energy up, he added.

Be sure to stretch your muscles before an outdoor winter workout, Dr. Goldwaser said, because muscles and ligaments are prone to tearing when they’re cold. He recommended dynamic stretches, which gently and briefly stretch various muscle groups. Dynamic stretches can be safer than static stretches, which you hold for longer periods of time, he said, because static stretches can stress cold muscles.

Whenever you exercise outdoors alone, you should tell someone where you’re going or bring a phone with you in case you get injured, Dr. Terrell advised. If you’re nervous about encountering animals or other risks, consider bringing pepper spray or bear spray with you, too, if it’s legal where you live.

Never exercise outdoors during a thunderstorm, Dr. Goldwaser said; the chance that you could be struck by lightning is small but significant enough to merit caution. Dr. Terrell suggested checking the weather forecast before an outdoor excursion to be sure that bad weather isn’t expected. If you do occasionally need to move your workout indoors, “have a plan B,” Dr. Terrell said, so that you can still get some exercise. I do barre videos in my basement, for instance.

Dr. Fleeter said that you should never exercise outside when the temperature or windchill is below -10 degrees Fahrenheit because the risk for frostbite is high. You may also want to stay inside when it’s slightly warmer, depending on what you’ll be doing. If you’re bicycling, you’ll encounter wind, which will make you feel colder, Dr. Fleeter said; he advises people not to ride bikes below about 15 degrees, and he advises against running at temperatures below 5 degrees.