Why the measured temperature is much higher than the weather forecast

The huge difference between the figure between the weather forecaster and the temperature measured by the people is because of the different measuring and measuring environments.

Specifically, the meteorological figure announced is the heat measured at meteorological tents (such as Stevenson Screen). Here, the thermometer is placed about 1.5 meters from the ground because if placed too close, it will measure the temperature of the entire ground, while placing too high, it will be biased by the temperature changed by the altitude. The base of the place must be green grass, not a road or concrete.

Stevenson Screen contains an air temperature thermometer made of wood, painted in white, with breathable slots on the side, placed on the grass about 1.5 meters high.

In addition, the temperature measuring device must be placed in the shade. The reason is that if the thermometer is in direct contact, it will absorb solar radiation, resulting in a higher measurement of air temperature. There is also a need to circulate air around the thermometer, maintaining a balance with the surrounding environment.

Moreover, meteorological agencies must also use specialized thermometers with high accuracy. In addition, published data is also collected at certain time frames and is usually the average number at a number of different measurement points. For example, the temperature measured in Cau Giay area may be higher than that in Phu Xuyen (same in Hanoi), which has a cause of urban effect .

Users measure the temperature in the usual way, placing it directly on the concrete floor, in the middle of the sun.

The usual measure is to put a thermometer in the middle of the road, on a sunny outdoor concrete floor. At this time, the recorded temperature is significantly higher than the weather agency's notice because the measuring environment is not correct, the thermometer also directly absorbs the heat from the sun, the road surface is up, not just measuring the heat alone. air level.

Similarly, the number showing the environment temperature (outdoor) on cars can be big difference, even up to a dozen degrees Celsius, because in addition to the difference due to the measuring environment, it is also affected by heat radiating. from car engine.