UK climate: What is the UV Index and why may it break UK information?

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Bright sunshine in the Lake DistrictImage copyright Getty Images

The UK may expertise a document UV degree of 9 on Thursday because the temperature continues to rise.

So what’s UV and why may information be damaged now?

What is the UV Index?

The UV Index (or UVI) is an ordinary worldwide measure of ultraviolet radiation emitted by the Sun – which penetrates the Earth’s environment and may trigger sunburn.

Index values begin at zero after which can rise above 10.

The larger the UVI, the better the potential for injury to the pores and skin and eyes – and in addition the much less time it takes for hurt to happen.

UV Index:

  • 1 to 2 = Low
  • three to five = Moderate
  • 6 to 7 = High
  • eight to 10 = Very High
  • 10+ = Extreme

Levels of UV radiation differ all through the day.

Highest readings happen within the four-hour interval round photo voltaic midday, which – relying on the place you might be and whether or not daylight saving time is utilized – is between 12:00 and 14:00.

Countries near the equator can expertise very excessive UV ranges in the course of the day all year long.

According to the World Health Organization (WHO), Nairobi in Kenya can see UV ranges above 10 all yr.

Majorca in Spain, will usually hit 9 in June and July.

But the Falkland Islands within the South Atlantic by no means normally will get above 5 in December and January – when it is summer time within the southern hemisphere.

What is the UV index within the UK?

UV ranges improve within the spring throughout the UK, reaching a peak in late June.

In this present spell of nice climate, we may see among the highest UV ranges ever recorded.

“Normally they’re about six or seven in the summer months,” says BBC Weather’s Matt Taylor. “Today we could hit a nine in some parts of southern England and South Wales.”

Why is the UV index so excessive now?

There are a lot of elements – not simply because many of the UK is cloud-free in the mean time.

“We’ve just passed the summer solstice so the sun is particularly high in the sky,” says Taylor.

“We’ve additionally seen ozone depletion at distinctive ranges throughout the northern hemisphere through the winter and spring, primarily on account of pure climate patterns.

“And with much of the northern hemisphere being under lockdown recently, pollution levels are lower. That stops the UV being scattered quite so much.”

Why is UV harmful?

We want daylight to maintain us in good well being, however getting sunburnt from an excessive amount of UV publicity – particularly for fair-skinned individuals – is not the one threat.

“UV is important for getting Vitamin D and keeping us healthy, but too much of it can cause skin cancer or eye cataracts,” says Dr Michaela Hegglin from the University of Reading’s Department of Meteorology.

“So slip into a shirt, slop on some sun cream, and slap on a hat and sunglasses during the hottest hours of the day.”

And bear in mind, the quantity of UV reaching your pores and skin isn’t pushed by the day by day temperature. UV ranges on a vibrant and breezy late April day might be about the identical as a heat sunny day in August.

“Your skin can burn just as quickly whether it’s 30C or 20C,” says BBC Weather’s Helen Willetts. “And don’t be caught out on cloudy days. UV will still penetrate thin clouds – so even if you don’t think it’s that sunny, you can still burn.”

Image copyright Reuters

What can I do to keep away from UV injury?

You ought to repeatedly apply a excessive issue sunscreen to stop pores and skin injury – particularly in case you are fair-skinned. You also needs to keep away from being out within the solar through the center of the day.

Sunglasses are additionally vital. Exposure to UV rays has additionally been linked to severe eye situations.