Night at the summit of El Capitan

[girolame]

Hello,

I plan to hike to the summit of El Capitan at the end of May (coming from Old Big Oak Flat Trailhead) and then to sleep at the summit

I'm seeking information about the weather at the top at the period of year. Are the nights cold ?

What kind of sleeping bag I need ? (Which temperature rating I need in fact)

For this experience, do I need a wilderness permit ?

Thank you,

Jérôme

[AlmostThere]

YES, you need a wilderness permit. http://www.nps.gov/yose/planyourvisit/backpacking.htm
And a bear canister: http://www.nps.gov/yose/planyourvisit/bears.htm
And something that will be comfy warm to below freezing - a sleeping pad and a sleeping bag. And a shelter, so if it rains you won't get all wet.

Nights can be below freezing all year round, potentially, depending on weather patterns. Or they can be warmer. But it's easier to cool off, than to warm up if you did not bring gear.