7 Things to Never Leave in Your Car in the Summer, From Medications to Plants

Cosmetics, Skincare, and Sunscreen

Of course, it's wise to reapply sunscreen throughout the day to protect yourself against the sun's strong rays—but don't leave that bottle baking in your car. The ingredients in skincare products and sunscreen can degrade (and leave your skin less protected) when exposed to direct sun and extreme heat.

The FDA directs consumers to keep sunscreen away from prolonged heat exposure and strong sunlight (like the kind found in a hot parked car), suggesting wrapping bottles and canisters in towels for an extra layer of protection. Also, keep your lipsticks and balms stored in your purse or back at home to avoid returning to a melted, waxy mess.

Medications and Supplements

Both prescription and over-the-counter medications can lose their effectiveness when exposed to extreme temperatures. According to a 2021 study published in the National Library of Medicine, most medications should ideally be stored at a temperature between 59 and 86 degrees Fahrenheit and a humidity level below 60 percent. A car parked in the summer sun can reach temperatures much higher than that, so take care to remove all medications from the car or keep a cooler on hand for their storage.

Electronics and Batteries

Smartphones, tablets, laptops, camera equipment, and external battery packs are particularly vulnerable to overheating. Damage to internal components can occur, and batteries, in particular, can swell, leak, or even burst when exposed to the high temperatures of a parked car.

Take your electronics with you when possible, and avoid leaving devices in cars for extended periods of time. When you have to leave items behind, be sure to store them out of direct sunlight, like in the trunk of your car (which will also keep them out of sight of thieves).

Food (Including Sealed Snacks)

Let’s start with the obvious: If you’ve ever returned to your car to find a chocolate bar reduced to a puddle or a granola bar turned gluey, you already know that snacks don’t fare well in the heat. Even shelf-stable items can degrade in quality when left in high temperatures. 

According to the USDA, perishables can become inedible within one hour if the outside temperature is 90 degrees Fahrenheit or higher. Additionally, with summer being primetime to visit national parks and hiking trails, remember that food left in your car can attract and endanger wildlife. Best to project to yourself (and any four-legged friends) by avoiding leaving food in the car. As a food safety measure, keep a compact insulated bag or small cooler in your trunk for grocery runs or takeout stops.

Plants

It's best to come straight home after taking a trip to the nursery. Most gardeners know that species can be sensitive to humidity and temperature fluctuations, and many plants won't be able to withstand the high temperatures. Give your new additions the best chance to thrive by not leaving them behind in your car.

Stationery and Craft Supplies

While it may seem prudent to keep a few pens or markers in your console—you never know when you might have to quickly write out a grocery list or thank-you card—the practice might lead to regret in the form of ink-covered cupholders.

In the high heat of your car, ballpoint pens can burst, wax-based supplies can melt into upholstery, and markers may leak or dry out entirely. Keep one capped and upright pen in a secure spot, and leave the other craft supplies at home.

Wine

Due to thermal expansion, a bottle of wine can uncork if left inside a hot car. But even when unopened, direct sunlight and UV exposure can affect a wine's flavors and aromas. Wine should always be stored in a cool, shaded place for the best experience, say winemakers and sommeliers.