What do you mean by cloudy weather?

In the weather forecast, cloudy means that there are more clouds in the sky and there is not enough sunshine, but the sky can still be seen through the cracks in the clouds. The total cloud cover accounts for 5/ 10-7/ 10 of the sky area.

Be careful of ultraviolet rays when you are active in cloudy weather. Ultraviolet ray is the general name of radiation with the wavelength from 10 nm to 400 nm in the electromagnetic spectrum, which can't be detected by human eyes, but too much ultraviolet ray may harm eyes.

The German Good Vision Association reminds that in cloudy summer, people should not forget to protect sensitive eyes, because some ultraviolet rays can still reach the surface through clouds, and long-term use may cause certain damage to eyes. The association also said that people who stay near the water for a long time should pay more attention to protecting their eyes because the water reflects light. If the eyes are damaged by too much ultraviolet rays, there will be symptoms such as redness, tears and eye muscle tension.