What should not be left in a car on a hot day? Here is your answer


Even as summer draws to a close and temperatures change, it’s important to take the time to learn what items you should keep out of the heat and in your car. Regardless of the outside temperature, your car’s internal temperature can reach extreme levels.

Even in cooler temperatures, your vehicle can quickly reach dangerous temperatures. Your car’s interior temperature can rise nearly 20 degrees Fahrenheit in the first 10 minutes, according to No heatstroke.org. So it’s safe to say that it’s best to leave some things out of your car on a hot day.

People and Pets

It may seem obvious, but knowing who is in your car is of utmost importance. In 2018 and 2019, 53 children died from vehicular heat stroke each year, according to the National Highway Transportation Safety Administration (NHTSA).

Heatstroke doesn’t just happen in the summer or in the Sunbelt states. This deadly problem can occur at any time of the year, in any weather condition, in any community, for any parent.

NHTSA also found that, on average, a child dies from heat stroke in a vehicle almost every 10 days in the United States.

To find out how quickly the temperature inside your car is rising, NHTSA created this online tool.

Pressurized cans

Aerosol cans carry warning labels for a good reason. When the temperature of the product increases, the pressure inside also increases, which can lead to problems. In some cases, like this woman in Arizonaintense heat in a car can cause the aerosol to explode and damage the car or a person.

Make sure that whenever you bring a pressurized canister into your car, it always goes out with you.

Solar cream

Intense heat can also damage the effects of sunscreen. According to CDC, Sunscreen without an expiration date has a maximum shelf life of three years and its shelf life is shorter if it has been exposed to high temperatures. Keeping your sunscreen out of the heat and the sun will help it last longer.


Another item to avoid keeping in a car on a hot day is your glasses. As spokesperson Susan Thomas saidLeaving your glasses or sunglasses on the dashboard is even worse because the windshield could catch sunlight like a magnifying glass.

Also, some reports say that heat can damage the mirror and anti-reflective coatings of the lenses and even cause the lens coating or even the lenses themselves to crack.

In extreme cases, frames can lose their shape and come loose around the ears, which can cause lenses to loosen or fall off.


Your electronics are another component to avoid leaving in direct sunlight or in a car on a hot day. Heat can damage hard drives, batteries, and other critical parts your electronics need to function properly. Data corruption/loss, battery leaks, or a complete shutdown are a few scenarios of what could happen when it overheats.

AAA advises removing electronic devices such as cell phones, iPods, etc. your vehicle, as the high heat can drain the batteries and possibly damage the internal components.

Also, some research showed that placing your device in direct sunlight can adversely affect the battery, especially if it has a lithium-ion battery.


In most cases, most medications should be left at room temperature. Dr. Sarah Westberg, associate professor at the University of Minnesota College of Pharmacy, says NPR that “extreme heat can reduce the effectiveness of some medications”. She added that “the Food and Drug Administration has said 75 to 77 degrees is the sweet spot.”

Same BaystateHealth.org explains that “the less that is said about the impact of improperly stored drugs and their potency-losing potential is that infections may not be cleared and disease may persist longer if antibiotics are involved.”

Also, medicines should never be stored in direct sunlight.

BaystateHealth goes on to say that “the drugs don’t tolerate sunlight very well and may lose effectiveness if stored on a windowsill.”

Beauty products

It’s understandable that you want to keep your cosmetics handy, but you should think twice about leaving them in your car on a hot day. In addition to destroying their active ingredients, extreme temperatures can melt cosmetics and leave you with a big mess to clean up.

According to the FDAtemperature changes and exposure to sunlight and air can cause color and texture changes and can cause products to smell.

Heat can also cause preservatives to break down and accelerate the growth of bacteria and fungi.

plastic bottles

Leaving plastic bottles in the car on a hot day has been a hot topic of controversy. Some say the water can be contaminated with harmful chemicals in the plastic that are released when sitting in extreme heat or direct sunlight. While other reports say there is no damage or cause for concern with the water bottle.

WaterDefense.org found that an unopened bottle has minimal health effects, but an open bottle is vulnerable to bacteria growth, which can lead to flavor or odor changes and more serious medical issues.

They even go so far as to say how those plastic water bottles can start a small fire. “The powerful rays of the sun have a lot of energy, enough to channel light into a high-powered magnifying glass, using the water bottle as a lens. Under the right conditions, this beam could burn through a car’s upholstery.

At the other end of the aisle, others, like Today and the International Bottled Water Associationreport that plastic water bottles are safe to consume under many conditions, including when left in cars, and claim that the packaging materials used by these bottles are FDA approved and safe to drink safe in different environments.

Whether you are for or against leaving plastic bottles in the heat, it is clear that keeping the bottles in a cool environment is better for storage and to avoid any unwanted issues.

Alcohol and wine

Leaving a six-pack of your favorite porter or a nice cabernet in a hot car is a great way to end up with six skunked beers and a ruined bottle of wine.

According Business Intern“Sunlight breaks down acids in beer, and the resulting compounds bind to sulfur proteins, giving it the dreaded ‘skunky’ taste.”

In the case of wine, VinePair reports that too much exposure to heat can lead to taste alterations, such as reds taking on a “tart, astringent character” and even the risk of the bottle spoiling or exploding, depending on the temperature.

A significant risk to note for wine and beer is the possibility of the bottle or can exploding. When left in temperatures above 70 degreesthe heat could cause wine bottles and beer cans to explode, leaving a mess and possibly injuring someone.


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