Firstly, there are two differences in climate of the cities. Climate type is one difference between two cities. Beijing has continental climate with three seasons a year: summer, winter and transition season- which is from middle of September to November. However, Hanoi has monsoonal climate with two seasons: wet season and dry seasons. Another difference between two cities is average annual rainfall. While an average annual rainfall is 2000mm in Hanoi, it is just 635mm in Beijing.
Secondly, the locations of Beijing and Hanoi have similar physical features. Both cities are built in alluvial plain. Beijing has got 16808 sq km in the north tip of the North China Plain. Similarly, Hanoi has got 921 sq km in the head of Red River delta.
Thirdly, the populations of the cities differ greatly in size and there is slight difference in their composition. Firstly, Beijing has approximately 16.800.000 people, whereas Hanoi has only about 1.524.000 people. Secondly, most of people live in Beijing are Han Chinese. In Hanoi, the majority of the people are Vietnamese.
Finally, there are similarities and differences in the economy of two cities. On the one hand, both cities are the well-known tourism cities. On the other hand, the majority of producer in Beijing are textiles and petrochemicals whereas the majority of producer in Hanoi is food processing.