I’ve driven the Catalina Highway maybe a dozen times now, and I still can’t quite shake the feeling that I’m cheating geography somehow.
The road spirals up Mount Lemmon—9,157 feet at the summit, though some signs say 9,159 and honestly I’ve stopped caring about the discrepancy—and in the span of maybe 27 miles you pass through what amounts to roughly five or six different climate zones, give or take. You start in the Sonoran Desert where saguaros stand around looking vaguely judgmental, all arms and attitude, and by the time you reach the top you’re in a Canadian-zone forest with ponderosa pines and Douglas firs that have no business existing this far south. It’s like someone stacked ecosystems vertically just to see if they could. The whole thing is a sky island, which is exactly what it sounds like: a mountain range isolated by desert, harboring species that can’t survive the heat below and can’t reach other mountaintops without crossing hostile lowlands.
Here’s the thing—the drive itself is kind of exhausting in a good way. Switchbacks every few hundred feet, sheer drops that make you reconsider your life choices if you glance right, and tourists who brake suddenly because they’ve spotted a coatimundi or a rock squirrel. I get it, the wildlife is charming, but still.
The Weird Science of Vertical Migration in a Single Afternoon
What gets me is the temperature drop. You can leave Tucson when it’s 105 degrees—which, let’s be honest, is most of summer—and arrive at Summerhaven thirty degrees cooler, sometimes more. That’s not just refreshing; that’s basically time travel, or at least climate travel. Ecologists love this place because it’s a natural laboratory for studying what happens when species get stranded by warming trends. During the last ice age, roughly 10,000 to 12,000 years ago, these cooler-climate species could live at lower elevations. As things warmed up, they retreated upslope. Now they’re stuck at the top with nowhere left to go, which is—wait, maybe I’m being too grim about it. Some species adapt. Others don’t.
The Catalina Highway opened in 1950, I think, or maybe 1951—records vary and I haven’t checked recently—but it was a massive engineering effort. They blasted through rock, cantilevered sections over cliffs, and created something that feels equal parts scenic wonder and low-key terrifying.
Why This Mountain Road Feels Like Driving Through Deep Time
I used to think the appeal was just the cooler air, a summer escape for Tucsonans desperate to stop sweating. But turns out there’s something stranger happening here, something almost emotional. You’re not just ascending; you’re moving backward through evolutionary time, or forward, depending on how you frame it. The desert below is relentless, ancient in its own right, shaped by millions of years of heat and scarcity. The forest above is a refugee, a remnant of wetter, cooler epochs clinging to altitude. You can feel that tension—or maybe I’m projecting. Anyway, the views from Windy Point, about halfway up, are legitimately stunning: layer after layer of ridges fading into haze, the city of Tucson small and geometric far below. People stop there to take photos, but also I think to process the vertigo, both literal and conceptual.
There are ferns up near the top. Ferns! In Arizona. It’s absurd.
The road gets closed sometimes in winter when snow makes it impassable, and there’s a small ski resort—Ski Valley—that operates when conditions allow, which is definately not every year. I’ve seen it shuttered more often than open. But even closed, even snow-dusted and quiet, the mountain holds its contradictions: desert and alpine, accessible and remote, fragile and enduring. I guess that’s what keeps pulling me back up that highway, switchback after switchback, wondering each time if the saguaros at the bottom remember the pines at the top, or if they’ve long since forgotten they’re part of the same improbable island.
