Idaho · Rock climbing · Almo

North Twin Sister

5 climbing routes at North Twin Sister in Idaho, grades range from easy to hard, sport and trad.

Photo: RuggyBearLA, CC BY 2.0 (via Flickr)

5 routes

5.7 – 5.11a

Trad · Sport

Is North Twin Sister open right now?

No closures listed

The National Park Service lists no closures for City of Rocks National Reserve.

As of Oct 25, 11:30 am MDT · Source: NPS · City of Rocks National Reserve. Agencies don't list every closure — check before you go.

Best time to visit North Twin Sister

Best months: April–June and August–October. Best months have typical highs of 55–85 °F, lows of 30 °F or warmer (32 °F where the station doesn't record snow), at most one snowy day and no more than 12 wet days.

Jan
35° / 16°
8 wet
Feb
39° / 19°
7 wet
Mar
48° / 27°
6 wet
Apr
55° / 33°
7 wet
May
65° / 41°
9 wet
Jun
75° / 50°
6 wet
Jul
86° / 59°
5 wet
Aug
85° / 57°
6 wet
Sep
74° / 48°
5 wet
Oct
60° / 35°
5 wet
Nov
45° / 24°
6 wet
Dec
35° / 17°
8 wet

Typical high / low (°F) and days with rain or snow, 1991–2020. Measured at Rosette, UT, 22.2 mi away at 5,685 ft. The station sits about 1,100 ft lower than this place, so expect it a little cooler here. This station doesn't record snowfall. Source: NOAA NCEI U.S. Climate Normals 1991–2020.

North Twin Sister is a climbing area in Idaho's City of Rocks National Reserve, managed by the National Park Service. It sits among a cluster of climbing spots, with the BLM Rock - West Corridor about 0.1 mile away and Indian Chief Rock about 0.2 mile away. The area has five routes, four of which are trad and one sport. Grades run from 5.7 up to 5.11a, with The Balcony Route at 5.10d and Safecracker at 5.11a. The Lowe Route, a trad climb first ascended by Greg Lowe and others in 1964, is 5.9+. For timing, late spring and early fall are the most comfortable. Typical averages from a nearby weather station in Rosette, Utah, show May highs around 65°F and September highs around 74°F, with July peaking near 86°F. Nearby, Marmot Boulder is about 1.4 miles away and Checkered Demon about 1.6 miles. Hikers can reach Register Rock, about 1.9 miles off, or the Flaming Rock Trail, about 2.1 miles away.