tucson was founded almost 100 years before phoenix in 1776 as a spainsh presidio.
phoenix didn't exist until the 1870's.
phoenix never had the core mexican population tucson had. until the early 1900's mexicans were the majority of the population in tucson.
what tucson didn't have was the salt river valley and its huge agriculture base. the santa cruz river, pantano wash, rillito creek, and tanque verde creek in tucson are all dry rivers. water only flows in them during rain storms.
tucson relys on underground wells to get almost all of its water. the only execption is the expensive government boondoggle CAP (Central Arizona Project) water now flows to tucson thru phoenix from the colorado river which borders california. the water is pumped up hill and costs many more times what ground lake water costs.
while the salt river and verde rivers in phoenix until they were damned up all had water flowing in them. after the rivers were damned up this resulted in a large number of lakes which supply water to phoenix.
while tucson is 100 miles south of phoenix the city of phoenix has hotter weather. this is because in the sonoran desert how hot you are is a function of how high you are. phoenix is about 1000 feet above sea level, and tucson is 2400 feet above sea level. in general phoenix is about 10 F hotter then tucson. the record in phoenix is 122 F while in tucson the record is 117 F. but its a dry heat. ill take a dry 115 degree day in phoenix any time over a 98 degree day with 98 percent humidity in chicago.
tucson is much wetter then phoenix. this is probably because tucson is closer to the gulf of mexico where the summer rain storms - which are called monsoons - form and head north across the mexican states of sonora and baja california into arizona, california, new mexico, nevada, and utah. tucson international airport gets 12 inches of rain a year, but many of other areas of tucson get 14 inches or more of rain. phoenix sky harbor aiport gets only 7 inches of rain a year, while the west valley gets 5 inches, and in the east valley 10 inches. las vegas nevada another desert city to the north only gets 3 inches of rain a year and very few of the summer monsoons that blow through tucson and phoenix.
it snows once every 50 years in phoenix. yes i once saw little weird white flakes drift thru the air and land on the ground where they melted. i think they were snow. maybe it will snow once more again in phoenix some time before i die. in tucson arizona and las vegas nevada it snows once every 10 years and the weird white stuff can actually stick to the ground.
the spanish left a monument to their superstitious christian beliefs in tucson. mission san xaviar del bac is one of the largest spanish missions in the u.s.a. was built before the american revolution. its much larger then the spanish missions in california. the mission is on the papago indian reservation about 5 miles from downtown tucson. and when i went it was free. the spanish used the christian religion to enslave the local indians just as they did through mexico.