How many degrees is the average temperature below for five consecutive days in autumn?

In climatology, beginning of autumn is usually defined as the day when the average daily temperature has stabilized below 22℃ for five consecutive days after beginning of autumn.

Divide four seasons according to climate and average temperature. The index is that the average temperature is below 10℃ in winter, above 22℃ in summer, and 10~22℃ in spring and autumn respectively. July to September in the lunar calendar, autumnal equinox to beginning of winter, September to 165438+ October in the solar calendar, and autumnal equinox to winter solstice in astronomy. In China, autumn begins in early autumn, passes through early autumn, Mid-Autumn Festival and late autumn, and finally ends in early winter.

The phenological standard studied by meteorologists is: after the intense summer heat, the average temperature for five days is stable below 22℃, which means that it enters autumn and ends when it is below 10℃.

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The main features of autumn are:

1. In autumn, the solar altitude angle decreases gradually, and the temperature decreases gradually; The autumn wind is cool, the summer heat is gone, the fruits are covered with branches, and the fields are golden.

2. Autumn is the harvest season, and many plants mature in autumn. In the subtropical region of the northern hemisphere, the temperature in autumn is obviously lower than that in summer.

3. In autumn, the cold air in the north is constantly invading, but the force is not very strong. Autumn weather often forms in northern China, and continuous autumn rain often appears in West China. The temperature will gradually drop in autumn, but it is generally slower than in winter.

4. Due to the difference of dry and wet conditions, there will be cold and rainy or dry and cool weather conditions in autumn in different regions. In the cold late autumn, due to the large temperature difference between day and night, the water vapor transpiration during the day will condense at night, either dew or frost.

5. The main meteorological disasters in autumn are: autumn rain in West China, cold dew wind in the south, frost and chilling injury at low temperature.

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