California · Rock climbing · Lake Arrowhead

The Slender One

Mid-range climb among six routes at Thumbspire Group.

5.10a
grade
Trad Gear
style

Is The Slender One open right now?

Closure in the area

There's a closure order in Mountaintop Ranger District. It doesn't name The Slender One, so check the source for the area it covers.

As of · Source: USFS · Mountaintop Ranger District. Agencies don't list every closure — check before you go.

Best time to visit The Slender One

Best months: April–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.

  1. Jan

    44° / 29°

    6 wet · 1 snow

  2. Feb

    45° / 30°

    6 wet · 1 snow

  3. Mar

    52° / 32°

    6 wet · 1 snow

  4. Apr

    60° / 36°

    4 wet · 1 snow

  5. May

    67° / 41°

    2 wet

  6. Jun

    76° / 49°

    1 wet

  7. Jul

    81° / 57°

    1 wet

  8. Aug

    82° / 57°

    1 wet

  9. Sep

    74° / 52°

    1 wet

  10. Oct

    63° / 43°

    2 wet

  11. Nov

    52° / 34°

    3 wet

  12. Dec

    43° / 29°

    5 wet · 1 snow

Typical high / low (°F) and days with rain or snow, 1991–2020. Measured at Lake Arrowhead, CA, 4.6 mi away at 5,205 ft. Source: NOAA NCEI U.S. Climate Normals 1991–2020.

One of six routes catalogued at Thumbspire Group, this climb sits in the middle of the crag's range between 5.7 and 5.10d.

Keep exploring — more climbs worth the drive