What are the climatic and geographical conditions in Xi 'an?

Xi belongs to warm temperate semi-humid continental monsoon climate. Four distinct seasons, hot and rainy in summer, cold and little rain and snow in winter, and even rainy weather in spring and autumn. The average annual temperature in Xi 'an and its suburbs is13.1~13.4℃. The annual extreme maximum temperature is 35 ~ 465438 0.8℃; Very low-16 ~-20℃. July is the hottest month in the whole year, with the monthly average temperature of 26. 1 ~ 26.3℃ and the monthly average maximum temperature of about 32℃. 65438+ 10 is the coldest month, with the monthly average temperature of -0.3 ~- 1.3℃ and the monthly average minimum temperature of -4℃ or so, with an annual variation of 26 ~ 27℃. Precipitation changes greatly during the year, and there is a great difference between rainy years and less rainy years, which can reach 590 mm at most. The seasonal distribution of precipitation is also extremely uneven. 78% of the rainfall is concentrated in May ~ 10, of which July ~ September accounts for 47% of the annual rainfall, and there are occasional heavy rains. The annual average relative humidity is about 70%. The annual average wind speed is1.8m/s, and the dominant wind direction throughout the year is northeast wind.

Spring (March-May): The temperature rises rapidly, but the temperature rise is unstable, and the weather of "suddenly warm and cold" often appears. The average temperature in Xi is 7.9℃ in March, 14. 1℃ in April and 19.4℃ in May. Spring rainfall accounts for about a quarter of the annual rainfall, and the average rainfall days in each month are 7-9 days. In spring, the temperature is pleasant and the weather is sunny, which is a good time for outdoor activities and travel.

Summer (June-August): It is characterized by hot and rainy weather. Xi is one of the four largest cities in China. July is the hottest month in the whole year, with an average temperature of 26.3℃. The average temperatures in June and August reached 24.8℃ and 15.3℃ respectively. The annual maximum daily temperature is equal to or greater than 35℃, and the average hot period is about 22 days. 1997 is the most, reaching 6 1 day. In the 38 years from 196 1 to 1998, extreme high temperature weather above 40℃ occurred in 9 years. Summer rainfall accounts for 37% of the annual rainfall. The average rainy days in each month are 8 ~ 1 1 day, and half of the rainstorm days in the whole year appear in summer.

Autumn (September ~165438+1October): In September, due to the influence of the Pacific subtropical high, Xi 'an has more precipitation and often rainy days. The monthly average rainfall is 99.5 mm, accounting for 19% of the annual rainfall, and the average rainy days for many years are 12 days. Autumn is suitable for cold and warm, and the cooling speed is fast. The monthly average temperatures are 65438 09.6℃, 65438 03.8℃ and 6.8℃ respectively. The average wind speed 1.5m/s is the season with the smallest wind speed in the whole year.

Winter (1 2 ~ February): It is cold and rainy in winter, and the average temperature of1month drops to -0.5℃. Due to the strong cold wave in winter, the extreme minimum temperature can be reduced to below-10℃. Rainfall is scarce and the climate is dry. The precipitation in three months is only 24 mm, accounting for only 4% of the annual precipitation.