Wasatch 100 Course

Weather is about as good as it gets for late May in the Wasatch. Highs climbing from 59°F today to 71°F by Sunday, low humidity, light winds under 14 mph, and essentially zero precipitation chance across the entire window. No afternoon thunderstorm threat identified — that's notable for this time of year and gives you full use of the 14h 40m daylight window without needing to rush off exposed ridgelines by early afternoon. Sunrise at 6:04 AM and sunset at 8:44 PM means if you're running a 30-mile segment, you can start at 6 AM and have an 8-minute-mile ceiling with hours to spare, or push longer efforts without headlamp concerns if you start early.

The one real variable is snow on the upper course. The snowpack data here is partially mismatched to the Wasatch (the stream gauge data is clearly from California), but Long Lake is showing 61 inches of depth with a falling trend — late-season consolidation, not active loading, which means firm snow in the morning softening by midday. On the Wasatch 100 course, the sections above 10,000 ft — Brighton, Scott's Pass, Ant Knolls — are likely still holding patchy to continuous snow on north and east aspects. Firm morning snow on those traverses will be faster and more stable than afternoon slush, so plan your timing to hit high-elevation sections before 11 AM if possible. Microspikes are worth throwing in a pack for the icy morning traverses if you're starting before 7 AM.

Hydration needs are moderate — temps in the 60s with low wind are comfortable but the dry Utah air and cumulative elevation on a 100-mile course means you'll under-sense thirst. Water sources on the upper course may be partially buried or reduced to snowmelt trickle; don't count on high-elevation sources being accessible or flowing well. Lower-elevation sections should have normal late-spring flows. Fires are clear within 50 miles, trail surfaces below snowline should be in good shape given the stable, dry conditions — typical late-May dirt and rock. This is a clean window, make the most of it.