Mountain Tiger Diablo

Mountain Tiger Diablo returns to Clayton, California on October 10th, offering a rigorous mountain running experience that challenges even the most seasoned athletes with its steep ascents and descents along Mount Diablo's summit trail. This race is part of the Mountain Tiger series, which began in 2025 with the launch of Mountain Tiger Donner Summit.
The morning of October 10th will see runners gathering at Mitchell Canyon Visitor Area for a challenging day ahead as they prepare to tackle the rugged terrain leading up and down Mount Diablo. The air is crisp and fresh around sunrise when temperatures hover near the average low, making early-morning starts ideal before conditions heat up later in the day.
Since its inception, Mountain Tiger Diablo has quickly become an iconic event among mountain runners seeking a true test of endurance on one of California's most formidable peaks. With each iteration, it attracts larger numbers of participants eager to experience this unique challenge and contribute to the growing legacy of hard-fought races across some of North America’s toughest terrain.
The 12-mile loop course takes runners directly up to Mount Diablo summit via Mitchell Canyon Road before descending back down an equally scenic but strenuous route. The climb is steep from the outset, with a significant ascent in the initial two miles as runners tackle Eagle Peak and Bald Ridge Trail en route to the summit. Once at the top, racers face a daunting descent that continues for six miles through Prospector's Gap and Back Creek Trail back down to Mitchell Canyon.
Elevation changes are extreme throughout this course; participants must ascend 1700 feet in just two-and-a-half miles before tackling even greater heights towards the summit. The descent is no less challenging, dropping a total of four thousand vertical feet over six winding miles through dense forest and rocky trails that test both mental grit and physical prowess.
Weather on October mornings around Clayton typically brings clear skies with an average temperature range between 13°C at dawn to nearly reaching 25°C by midday. Humidity averages near 58%, providing a comfortable yet unpredictable environment where runners must stay hydrated while navigating varied trail conditions that shift from firm and slightly soft underfoot during wetter periods.