than and sometimes reaching . Sunny skies and clear nights can be expected throughout the year. Many severe thunderstorms with strong winds and sandstorms reach the region in summer. Rainfall is scarce but it is more prominent in the summer. In the winter, daytime temperatures can be hotter than but at night the temperature can fall to . Snow in Ciudad Obregón is nonexistent, but hailstorms can occur during cold fronts. The extreme temperatures recorded in the box below between 1939 and 2016 were recorded at the Downtown Station of Ciudad Obregón, Sonora. City origins Cajeme Municipality has as its head Ciudad Obregón. Its first settlers established themselves in the neighborhood called Plano Oriente, as irrigation canals made by the Richardson company around 1910 and two years later, the South Pacific railroad established a station called Cajeme. The town of Cajeme was initially a part of Cocorit Municipality until its elevation to Municipal Seat on 28 September 1927. The first city government was established on 1 January 1928. The 28 July 1928 decree stated that "the city is known now with the name of Ciudad Obregón, the town formerly known as Cajeme." In 1937 another legislation stated that Cajeme be the name of the Municipality and Ciudad Obregón its seat. In 1950 Ciudad Obregon had a population on 120,000. Roots and traditions The native Yaqui people are settled in eight towns, Potam, Huirivis, Torim, Cocorit, Bacum, Vicam, Rahum and Belem. from the city is the first of the eight Yaqui towns that make the autonomous territory of these people known for their independent character, because it is one of the few American ethnic groups not dominated militarily by Spanish colonialists. Yaqui history informs the defense of their territory and culture, an ancestral culture enriched by rites and traditions of which the Deer Dance stands out, a symbolic representation of the hunt for this animal. Demographics Ciudad Obregón is the second largest city in Sonora (after state capital Hermosillo) with a 2010 census population of 298,625 People. Its municipality of Cajeme had a population of 409,310. the per capita income for the municipality of Cajeme was $10,940 and the Human Development Index was 0.8635. Government and economy In Ciudad Obregón lies the seat of the municipal government of Cajeme. The government's exercise rests with the Municipal President and his cabinet, elected every three years. Of the twenty-one Congress of the State