Science, Tech, Math › Science Why Car Interiors Get So Hot in Summer Share Flipboard Email Print Yasir Nisar/Moment/Getty Images Science Weather & Climate Understanding Your Forecast Storms & Other Phenomena Chemistry Biology Physics Geology Astronomy By Tiffany Means Meteorology Expert B.S., Atmospheric Sciences and Meteorology, University of North Carolina Tiffany Means is a meteorologist and member of the American Meteorological Society who has worked for CNN, the National Oceanic and Atmospheric Administration, and more. our editorial process Tiffany Means Updated July 03, 2019 We've all heard the saying, "If you can't take the heat, get out of the kitchen." But during summer, you could insert the word car into that sentence just as easily. Why is it that your car feels like an oven, no matter if you park in the sun or shade? Blame the greenhouse effect. A Mini Greenhouse Effect Yes, the same greenhouse effect that traps heat in the atmosphere and keeps our planet at a comfy temperature for us to live is also responsible for baking your car on warm days. Your car's windshield not only allows you an unobstructed wide view while on the road, it also allows the sunlight an unobstructed pathway inside your car's interior. Just like , the sun's shortwave radiation passes through a car's windows. These windows are only warmed a little, but the darker colored objects that the sunrays strike (like the dashboard, steering wheel, and seats) are heated immensely due to their lower albedo. These heated objects, in turn, heat the surrounding air by convection and conduction. According to a 2002 San Jose University study, temperatures in enclosed cars with a basic gray interior rise approximately 19 degrees F in 10 minutes' time; 29 degrees in 20 minutes' time; 34 degrees in half an hour; 43 degrees in 1 hour; and 50-55 degrees over a period of 2-4 hours. The following table gives an idea of just how much above the outside air temperature (°F) your car's interior can heat up over certain periods of time. Time Elapsed 70 °F 75°F 80°F 85°F 90°F 95°F 100°F 10 minutes 89 94 99 104 109 114 119 20 minutes 99 104 109 114 119 124 129 30 minutes 104 109 114 119 124 129 134 40 minutes 108 113 118 123 128 133 138 60 minutes 111 118 123 128 133 138 143 >1 hour 115 120 125 130 135 140 145 As you can see, even on a mild 75 degree day, the inside of your car would warm to triple digit temperatures in just 20 minutes! The table also reveals another eye-opening reality: that two-thirds of the temperature spike happens within the first 20 minutes! This is why drivers are urged not to leave children, the elderly, or pets in a parked car for any amount of time -- no matter how seemingly short -- because contrary to what you'd think, the bulk of the temperature rise happens within those first few minutes. Why Cracking the Windows is Useless If you think you can avoid the dangers of a hot car by cracking its windows, think again. According to the same San Jose University study, temperatures inside a car with its windows cracked down rise at a rate of 3.1 °F every 5 minutes, compared to 3.4 °F for closed windows. The just isn't enough to significantly offset the . Sunshades Offer Some Cooling Sunshades (shades that fit inside the windshield) are actually a better cooling method than cracking windows. They can reduce your car's temperature by as much as 15 degrees. For even more cooling action, spring for the foil type since these actually reflect the sun's heat back through the glass and away from the car. Why Hot Cars are a Hazard A stifling hot car isn't only uncomfortable, it's also dangerous to your health. Just like overexposure to high air temperatures can cause heat illness such as heatstroke and hyperthermia, so can but even faster since because they. this leads to hyperthermia and possibly death. Young children and infants, the elderly, and pets are most susceptible to heat illness because their bodies are less skilled at regulating temperature. (A child's body temperature warms 3 to 5 times faster than an adult's.) Resources and links: NWS Heat Vehicle Safety: Children, Pets, and Seniors. Heatstroke Deaths of Children in Vehicles. http://www.noheatstroke.org McLaren, Null, Quinn. Heat Stress from Enclosed Vehicles: Moderate Ambient Temperatures Cause Significant Temperature Rise in Enclosed Vehicles. Pediatrics Vol. 116 No. 1. July 2005. How to De-Ice Your Windshield Using Science Should I Break a Car Window to Save a Dog in a Hot Car? What Exactly Is New Car Smell? 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