Tucson is a city in Arizona, United States. It is the seat of Pima County. It is 118 miles (188 km) southeast of Phoenix and 60 miles (98 km) north of the Mexican border. It is where the shooting of senator Gabrielle Giffords took place. Arizona has many deserts. It is visited by many people to escape cold weather. Tucson has a population of 531,641 as of 2015 and is the second populated city in Arizona behind Phoenix. The city has a mean elevation of 2,400 feet. The climate of Tucson is a arid desert climate with very hot summers and mild winters. The monsoon occurs in mid June and ends around late September in the Tucson area.