The ultimate source of energy and life on our planet is solar radiation.
Over the last week or so we have been lucky enough to see a prolonged spell of high pressure dominating the UK, which gave a largely settled period of weather with plenty of sunny spells and therefore plenty of solar radiation.
Sunshine hours are increasing quickly, as is the height to which the Sun climbs in the sky each day.
A ‘higher’ Sun means that there is a smaller amount of atmosphere the radiation has to pass through before reaching the surface.
The Sun’s rays now have the same intensity as they do in mid-August, beaming down energy in different forms, ranging from Infrared to Ultra-Violet (UV) light, as well as the visible light that we see.
The UV index is a measure of the amount of the Sun’s radiation emitted in the Ultra-Violet wavelengths reaching the ground.
This UV index, which you sometimes see in forecasts, represents UV intensity around the Sun’s highest point in the day, called solar noon, which is halfway between sunrise and sunset.
The UV index at this time of year is typically five on a sunny day, which is plenty enough to get an early tan!
For the British Isles, the maximum possible UV levels continue rising until the Summer Solstice on June 21, by which time, a UV index of seven (or under exceptional circumstances even eight) can be achieved in the area under clear weather.
Whilst sufficiently high to burn unprotected skin in less than half an hour, this is still much lower than found elsewhere across the world.
In Greece, Spain and Italy for example which are at lower latitudes, values can peak at around 10 in the June midday sunshine.
Closer to the Equator, where the Sun is right overhead, higher values can be achieved, making it potentially dangerous to be outside without adequate protection from the sun.
Back in the area, the prolonged dry and sunny weather has continued through this week, and is expected to last for the next couple of days.
Friday and into the weekend are looking increasingly unsettled, with outbreaks of rain likely at times.