How hot is this weather?

People get tanned because of ultraviolet rays. In the shade, ultraviolet rays only weaken, but they still exist.

The ultraviolet intensity is divided into five levels: 1 level is the weakest, which usually indicates rain; Level 2 is weak and generally cloudy; Level 3 is medium, generally cloudy, and occasionally a little sun can be seen from the clouds; Level 4 is strong, generally sunny; Level 5 is the strongest,

The weather is especially sunny at ordinary times. April-September is the season with the strongest ultraviolet radiation; 10 is the strongest period of ultraviolet radiation from morning to 2 pm; Noon is the peak of ultraviolet radiation.

Extended data:

Precautions for sun protection:

1, pay attention to SPF index

SPF value is the main content marked on every bottle of sunscreen. Simply put, it is the time multiple of skin's resistance to ultraviolet UVB. Generally, the skin of the yellow race can be protected from sun 15 minutes on average, so using SPF 15 anti-ultraviolet products will have a sun protection time of about 225 minutes. Objectively speaking, the level of sun protection index reflects the ultraviolet protection ability of sun protection products. The higher the SPF index, the greater the protection, but the increase of SPF value is not proportional to the ability to shield ultraviolet rays.

2. PAy attention to the pa index.

The correct expression of PA is ProtectionofUVA, and its degree is marked with+,++and++. The more "+",the better the anti-UVA effect. Usually, the strength of PA is represented by+,and one more+means that the effective protection time is prolonged. Specifically, the effective protection time of PA+ is about 4 hours. The effective protection time of PA++ is about 8 hours. PA+++ super protection.

3. Pay attention to the amount of sunscreen.

The premise of ensuring that the protective effect is consistent with the product logo is that you apply two milligrams of sunscreen products to one square centimeter of skin. However, the survey of consumers' habits shows that the average woman only uses 0.5 mg per square centimeter at a time, so the protective effect can only reach 1/3 or even 1/4 indicated on sunscreen products.

Baidu encyclopedia-ultraviolet