It's called 'Blue Hour' and it's known as the time between sunset and darkness, when the sky turns amazing shades of blue.
The national park shared a picture of the sight on its Facebook Page this week.
During the spring climbing season, it can take several days to climb Yosemite's towering cliffs.
But when climbers settle down for the night... you can watch their headlamps turn on when the stars come out.
This photo shows climbers with their lights on El Capitan -- but you can see sights like this along many routes through the Yosemite Valley at night.