Xinjiang 40℃ VS Jiangsu, Zhejiang and Shanghai 40℃, what’s the difference?

#Zhejiang is already too hot to work#! In recent days, as a representative of the core high-temperature areas in the south such as Jiangsu, Zhejiang and Shanghai, Zhejiang has been frequently searched for hot topics; and in Turpan, Xinjiang, many people are enjoying the sand therapy and dehumidification trip by taking advantage of the scorching heat, which makes Zhejiang netizens who are holding air conditioners to "extend their lives" can't help but shout-

"Your 40℃, my 40℃, why are they different?!"

At 15:00 on August 7, Zhejiang once again topped the national high temperature list. Photo: China Central Meteorological Observatory

Is this a mistake in everyone's perception? Or is it a mistake in the weather station's report? In fact, no one is wrong.

In the forecast of the meteorological department, in addition to the air temperature, there is often also a perceived temperature, which is the "temperature felt" by everyone. It is because of it that the same temperature has different "hot" and "cold" temperatures.

The difference between air temperature and perceived temperature. Photo: China Meteorological Administration WeChat official account

Xinjiang 40℃ < South 40℃

According to the regulations of the World Meteorological Organization, the temperature announced by the meteorological department is the temperature measured by the thermometer in the louvered box. The louvered box must be set on the lawn, 1.5 meters above the ground, with a relatively open area around it to eliminate the influence of external factors and ensure the accuracy of the measured value.

Open the louvered box and you can see various temperature gauges, including the highest temperature gauge, the lowest temperature gauge, the dry-bulb temperature gauge, and the wet-bulb temperature gauge. Photo/Xinhuanet Science

The perceived temperature refers to the different feelings of cold and warmth produced when the body comes into contact with the air, which is mainly affected by many factors such as temperature, humidity, wind speed and sunshine.

In the summer, when the temperature is high, the higher the relative humidity and the lower the wind speed, the higher the perceived temperature. This is because the human body regulates temperature mainly through sweating, and dry air absorbs sweat and takes away heat; when the wind speed increases, the amount of air in contact with human skin increases, and the heat dissipation efficiency will be higher. In an air environment with high humidity and low wind speed, the sweat on the skin surface cannot be absorbed and the heat cannot be dissipated, which will make people feel hotter.

The temperature comparison table released by the National Oceanic and Atmospheric Administration (NOAA) of the United States. Photo/China Weather Network

The air humidity in southern areas such as Jiangsu, Zhejiang and Shanghai is relatively high, while the climate in Xinjiang is dry. Therefore, under the same temperature conditions, 40℃ in the south will often feel hotter than 40℃ in Xinjiang.

Weather conditions in Changxing, Zhejiang at 12:00 on August 5 and in Toksun, Xinjiang at 13:30 on August 1. Photo: China Meteorological Administration

Take Changxing, Zhejiang, which topped the national high temperature list at 12:00 on August 5. Although the actual temperature was 40℃, the humidity was 48%, resulting in a perceived temperature close to 46℃. At 13:30 on August 1 in Toksun, Xinjiang, the actual temperature was close to 40℃ and the humidity was only 23%. The final perceived temperature was slightly higher than the air temperature, at 41.3℃.

Xinjiang 0℃>South 0℃

As the saying goes, the skin is cold in the north and the bones are frozen in the south. Affected by wind and humidity, in winter, the perceived temperature is different between 0℃ in Xinjiang and 0℃ in the south.

When the temperature is low in winter, the human body temperature is higher than the ambient temperature, so it will dissipate heat outwards. Water can transfer heat better than air. In the south where the relative humidity is often above 70% in winter, the heat of the human body will be continuously transferred out through the "water" mixed in the clothes, making people feel particularly damp and cold.

In northern Xinjiang, the stronger the wind, the lower the perceived temperature is than the actual temperature. But if you wear enough clothes, you can block the cold air and prevent internal heat loss.

Photo/China Weather Network

According to the Central Meteorological Observatory's temperature formula, at 5°C, the relative humidity reaches 70%, and the perceived temperature is 2.6°C; if the relative humidity reaches 90%, the perceived temperature is only 1.2°C. Under the same temperature conditions, when a force 7 gale blows, the perceived temperature is 2.5°C, and it will only reach 1.8°C when a force 9 gale is added.

In winter, it is common for the air humidity in the south to reach over 70%, while it is not so easy for strong winds of level 7-9 to continue in the north. Therefore, under the same temperature conditions, it is more likely for people to feel cold in the south.

Xinjiang 10℃≠Xinjiang 10℃

In Xinjiang, even at 10℃, you will feel warm in spring, but still feel cold even with a coat on in autumn. This is also caused by the difference in perceived temperature.

On April 4, the willow trees in Liyushan Park in Urumqi City sprouted new buds. Photo by Zhang Wande, a reporter from Xinjiang Daily/Shiliuyun

Spring and autumn are both transitional seasons, but the temperature trends are opposite, and the feelings they bring are also very different. In Xinjiang, where the seasons change quickly, this process is more obvious.

In spring, the body, which has experienced a long winter, has become accustomed to the cold, so a temperature of 10°C feels very warm. In autumn, however, the body, which has experienced a hot summer, is still accustomed to the heat, so 10°C seems very cold, hence the sayings of "cover up in spring" and "keep cold in autumn".

In addition, the humidity in Xinjiang is relatively high in spring, while the humidity is relatively low in autumn, which is also an important factor affecting the perceived temperature.

Studies have shown that under the same temperature conditions, changes in relative humidity, wind speed and other factors can cause the perceived temperature to differ from the actual temperature by 4°C to 6°C, or even more. However, we can still arrange our lives and travel reasonably based on a series of services provided by the meteorological department, such as the comfort index, clothing index, and UV index.

(Shiliuyun/Xinjiang Daily reporter He Yanhong)