Why a parked car hits 70C in the sun

A parked car can become much hotter than the air around it because sunlight passes through its glass and is absorbed by the dashboard, seats and other dark surfaces. Those surfaces warm up and transfer heat into the cabin, while the closed car limits how quickly that heat escapes. In a University of Baghdad experiment conducted on clear summer days, researchers recorded cabin air at 70°C and dashboard temperatures approaching 100°C in an unshaded car. The useful lesson is not simply that cars get hot. It is that stopping sunlight from reaching interior surfaces can make a meaningful difference to what you touch when you return.

The familiar description is the greenhouse effect. Solar radiation enters through the glass and heats the cabin's surfaces. Those surfaces then emit heat and warm the surrounding air. With the doors and windows closed, heat accumulates faster than it can be removed.

That distinction matters when choosing sun protection. A windscreen shade intercepts sunlight before it strikes much of the dashboard, so its clearest benefit is reducing surface temperature. The Baghdad study found an internal cardboard shade cut dashboard temperature by 40 per cent but did not reduce cabin air temperature. Separate Florida Solar Energy Center research found conventional windscreen shades reduced interior air temperature by an average of about 15°F, or 8°C, in its tests. Different cars and conditions produce different results, but neither study supports treating a shade as portable air conditioning.

In the UAE, window film provides another layer. Current rules permit tinting up to 50 per cent on eligible vehicle windows, excluding the front windscreen.

Coverage matters most with a windscreen shade or dashboard cover. Large gaps leave sizeable areas exposed to direct solar radiation. For window film, look beyond a headline infrared figure. Total Solar Energy Rejection, or TSER, describes the proportion of total solar energy rejected by filmed glass, while Visible Light Transmittance, or VLT, tells you how much visible light passes through. Those figures describe different properties, as 3M's technical guidance explains.

This is the most direct response to the large piece of glass facing the dashboard. The following products is indexed as a black and silver polyester shade measuring approximately 150cm by 74cm, with a universal fit design. Its job is straightforward: cover as much of the windscreen as possible while the car is parked and reduce direct solar loading on the dashboard. The research suggests that surface protection is the reason to buy one, rather than expecting a dramatically cool cabin. Check the dimensions against your windscreen before ordering, particularly for very small cars or broad SUV glass.

A steering wheel cover approaches the problem differently. It does not stop the cabin heating up, but it adds a layer between your hands and the wheel surface. The supplied model is listed for steering wheels around 14.5 to 15 inches in diameter and uses a microfibre leather construction with a textured finish. That makes it a practical companion to a windscreen shade in a UAE summer, especially when part of the wheel remains exposed as the sun changes angle. Measure the wheel first. A steering cover needs a secure fit and should never be treated as a substitute for shading the car itself.

Tint works while you are driving as well as when the car is parked, so it tackles solar gain through more than the windscreen alone. The following product is indexed as a light blue, non metallic nano ceramic PET film, 20 inches wide and 10 feet long, with 80 per cent VLT. Product specifications also claim 46 per cent TSER and 99 per cent UV rejection. Those figures should not be confused: TSER is the more useful overall solar energy measure. Installation and local tint compliance matter, and the front windscreen is excluded from the UAE's general 50 per cent tint allowance.

A dashboard cover focuses on the surface that receives some of the strongest direct sunlight through the windscreen. Its value here is therefore surface protection rather than lowering the temperature of the entire cabin. Fit deserves particular attention. A cover should sit securely and must not obstruct vents, displays, sensors or airbag deployment areas. Used with a correctly sized windscreen shade, it provides another physical layer over a high exposure interior surface rather than making an exaggerated promise about cooling the whole vehicle.

The 70°C figure is credible under hot, sunny test conditions, but the useful takeaway is where that heat comes from. Sunlight heats interior materials first, then those materials heat the cabin. A windscreen shade interrupts that process at one of its biggest entry points and is the simplest recommendation here. The SHOWAY shade is our top pick because it directly addresses dashboard solar loading without permanent installation. Tint can broaden the effect across the windows, while covers concentrate on individual surfaces.

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