What is the reason for the low temperature in Lanzhou in July?

The temperature in Lanzhou is not low.

Please read the following:

In early July, the temperature in Lanzhou remained high under the control of the mainland heating mass. Before 10, except for rainy weather on the 2nd, the temperature was 26.6 degrees Celsius, and the other 9 days continued to be hot and muggy, and the highest temperature was always there.

Hovering between 32 and 35 degrees Celsius. According to statistics, the average temperature in Lanzhou in the first ten days was 25.9 degrees Celsius, which was as high as 4.3 degrees Celsius higher than the average temperature for many years, and was the highest value in the same period since Lanzhou 1933 had meteorological records. The continuous high temperature of 3 ~ 10 is also rare for many years. According to the forecast of Lanzhou Meteorological Bureau, because the heating air mass over Lanzhou is relatively stable at present, this high temperature weather will continue, and citizens should be prepared for heatstroke prevention and cooling.