The UV index is one of the most important but often less well-known parts of weather forecasting. UV stands for ultraviolet, and it’s a type of radiation that is emitted by the sun. Small amounts of UV rays from the sun can be hugely beneficial — they are essential in the body’s production of vitamin D –– but if the level gets too high, they can also be dangerous.
That is why it’s essential to keep track of emissions.
To do that, meteorologists measure the UV index. You’ll likely have seen this measurement already if you use a weather app to keep an eye on the forecast.
What Is the UV Index?
The UV index is a measure of the strength of ultraviolet radiation emitted by the Sun. It’s a standard international way to measure UV radiation. The index starts at 0 and goes up to a high of 10. In extreme cases, the UV level can hit 11. It’s an international standard measurement, so it’s measured and reported in the same way no matter where you are.
The strength of ultraviolet radiation varies depending on several factors:
- Time of year
- Weather conditions such as the amount of cloud cover
Levels of UV radiation can also vary throughout the day, with countries near the equator often experiencing very high UV levels in the middle of the day throughout the year. Nairobi –– the capital of Kenya –– is situated very close to the equator and can experience UV levels above 10 all year.
The UV index is not linked to temperature. UV levels can be just as high on a spring day as in the height of summer. If you don’t have access to a phone, a good rule of thumb is that If your shadow is shorter than you are, you are being exposed to higher levels of UV radiation.
What Can I Do to Avoid UV Damage?
If the UV Index is high, there is a more significant potential for damage to skin and eyes. By tracking the index, you know when you need to wear sunscreen and sunglasses.
Sunglasses aim to block out UV rays and avoid any damage the sun can cause your eyes. When you’re buying sunglasses, you’ll notice that they are divided into different categories depending on their level of protection. The two most common types are:
- Category 3 — dark lenses for bright days (most sunglasses today fall into this category)
- Category 4 — very dark lenses for intense sunshine
When it comes to protecting your skin, there are two different types of UV radiation to be aware of. UVB rays are responsible for producing sunburn and causing skin cancer, while UVA rays play a more significant role in premature skin aging, although they can also lead to skin cancer. While sunscreen has traditionally been more effective at protecting against UVB rays, you should look for a product that contains both.
Wherever you’re spending the summer, make sure to prepare for high UV levels adequately!