Half Dome via Cables

Weather is as clean as it gets for late May in the Valley. Highs in the 67–69°F range with overnight lows around 49–51°F, light winds under 10 mph, and essentially zero precip chance Friday through Saturday. Sunday introduces a slight chance of afternoon showers and thunderstorms (14%) — that's not a trip-ender, but the Half Dome cables are non-negotiable exposure during electrical activity. Plan your summit day for Friday or Saturday if you have flexibility. If Sunday is your cables day, start early enough to be off the summit and descending by noon.

Snowpack at 31 inches is present in the high country but it's late May and the route sees heavy traffic — expect the cables themselves to be up and in decent shape, but plan for patchy snow on the approach above Sub Dome, particularly on north-facing slopes. Microspikes are worth carrying for those sections. The SNOTEL data shown doesn't directly correspond to the Yosemite high country, so treat the 31-inch depth figure as a general regional indicator rather than a precise read on the Half Dome route. Afternoon solar warming will soften any snow you encounter, so if you're crossing snowy sections on the descent, earlier in the day is more stable footing.

Stream flows across the five gauges are all at or well below median, none trending upward. No crossings on the standard Half Dome route via the JMT or Mist Trail approach are going to be problematic this weekend. Merced River crossings on the valley floor are bridged anyway. No active fires within 50 miles, air quality is clean, no smoke impacts expected.

With 14+ hours of daylight and sunrise at 5:44 AM, you have enormous flexibility on start times. If you're day-hiking the cables from a backpack camp at Little Yosemite Valley, a 5–6 AM start from camp gets you to the summit before any crowds and well ahead of any Sunday afternoon weather. The golden hour window (7:30–8:07 PM) on Friday and Saturday will be spectacular from the valley — plan camp accordingly if that matters to you.