We went up the Mt. Lemmon Highway, a winding road that starts at 2500 ft. in the saguaro studded Sonoran Desert foothills. It rises up to 9200ft. through several gradual ecological changes, to a tall pine forest where there is a ski lift. I can often be sitting by a swimming pool sunning in Tucson and looking up at snow in the wintertime. There isn't snow all of the time up there. Only occasionally. Then when it is 100F in Tucson in the summer, it is a lovely warm and cool up there in the trees. There is a small enclave town up there called "Summer Haven."
Along the way up the road, there is a transition from what you might call a dry summer where you live. It then rises through grassland, smaller trees and then pines and berries. There are consequent changes in seasons in the time that it takes to drive up the road.
The Catalinas are a "sky Island":
https://thefreerangenaturist.org/2015/10/05/an-introduction-to-arizonas-sky-islands/We have it all, so to speak.
The geology is incredible. There are many hoodoos and formations. There are grand vistas out to Mexico, New Mexico, far north and then down at Tucson far below. It is like city lights from an aircraft, up there at night, after stepping out of the contrasting deep woods, or rocky plain, spectacular.
As the crow flies, it is not as great a distance as 30 0r forty miles. To drive up the highway can be 30 or forty minutes. I did it in my BMWtii in 20 once. It is a wonderful afternoon, just to drive, stop at vista points along the way, do pizza at the town, take a walk, etc. Then, again, there are trails and camping to spend days wandering or sitting.
The east side of Tucson has the Rincon Mountains bordering it, no road, but the same sort of conditions. South are the Santa Ritas, a drive into Madera Canyon, or several other dirt roads into scrub canyons, then a hike from there to an altitude higher than Mt. Lemmon (to the north).
The Tucson Mountains (west) and Tortolitas (NW) are comparably more diminutive at only 4000 ft. They are desert, ranging into grasslands, with micro climates.
I'm not sure what the "eastern 'catchment'" is that you refer to. The east-side gets wash-off and rainfall from both the Rincons and Catalinas and is pretty lush desert with the Tangue Verde Creek running through it, where rain and snow melt can range fed from the mountains. Redington Pass is out there. That river is surrounded with thick mesquite bosque, tall cottonwoods, etc.
Jbee