Car windows will block most, but not all harmful sunlight
It's the ultraviolet radiation (UV rays) in sunlight that causes sun burn. It's also one of the main causes of skin cancer.
You're more likely to develop skin cancer if you have fair skin that burns easily, lots of moles or freckles, red or fair hair, or light-coloured eyes.
There are two types of UV in sunlight and exposure to either increases your risk of developing skin cancer.
UV levels inside your car will depend on the type of glass, your direction relative to the sun, and whether you've got the windows open or closed.
The Sun Protection Factor (SPF) is mainly a measure of UVB protection. The higher the better.
A separate star rating (one to five) tells you how much UVA protection it gives.
It's best to choose a ‘broad spectrum’ sunscreen that can protect you against UVA and UVB.
(updated March 2016)