It's a roadside high altitude paradise for bouldering.
There are some routes on the cliffs directly above the road but most people come here for the bouldering. It's cold and windy which is good as the rocks feature a lot of slopers. There are also crimpy walls, overhangs, slabs and some fantastic mantle problems. If it's sunny you can always find problems in the shade. Sometimes you will simply just 'stick' to the rock because of the altitude and cold. In the shade on a cold dry day it's the best conditions I've seen for slopers.
A small group of buildings and a small tea shop make the place itself so you can get some basic snacks, drinks and meals. To stay longer you might like to bring some supplies and camp in nice meadow just down from the road or stay in one of the many 'goofas'(caves) nearby. It's a roadside wonderland for bouldering and has some absolutely classic problems. The real season is between the end of May and end of October.
Proper info and topos for the problems: Chota dara
It's directly halfway on the Manali to Kaza bus route which starts at 5-6 am from Manali (4-10 hrs journey) Otherwise shared jeeps and rides are possible. From Chattru it's 17 km up the road with a few hundred metre height gain. It's further from Rohtang pass and closer to Spiti valley proper so slightly less precipitation than Chattru.
The climbing season diagram below is wrong but you could use it in the opposite way (real season is off season) so when the green line goes the lowest you want to be there.
Weather station 32.8 miles from here
Featured Route For Chota dara