Do you go to the dungeon?

Climbing

A lot of this is from Veins of the Earth, fantastic book♥

Route Types

Abseiling Climb

Rope (already fastened up there) & Peace & Quiet

No roll needed.

Fighting or Distraction

Strength (study for DC).

Level three thief Second Story Work gets expertise on their strength roll at this route, if they don't already have expertise in strength.

Level nine monk Unarmored Movement can run here without if they are unencumbered but when their movement ends they need to roll to grab hold, or be on solid ground.

No rope?

Counts as Hard Climb, see below.

Sloping Climb

Peace & Quiet

No roll needed.

Fighting or Distraction

Strength (study for DC).

Level three thief Second Story Work gets expertise on their strength roll at this route, if they don't already have expertise in strength.

Level nine monk Unarmored Movement can run here without if they are unencumbered but when their movement ends they need to roll to grab hold, or be on solid ground.

Hard Climb

Encumbered

No chance.

Rope (already fastened up there) & Peace & Quiet & Unencumbered

No roll needed.

Fighting, Distraction or lack of Rope

Strength (study for DC).

Level three thief Second Story Work gets expertise on their strength roll at this route, if they don't already have expertise in strength.

Level nine monk Unarmored Movement can run here without if they are unencumbered but when their movement ends they need to roll to grab hold, or be on solid ground.

Tip! If you make it, set a rope for your friends with hammers, pitons etc.

Very Hard Climb

Encumbered

No chance.

Unencumbered

Strength (study for DC).

Level three thief Second Story Work gets expertise on their strength roll at this route, if they don't already have expertise in strength.

Human Limit Climb

Encumbered or no Second Story Work

No chance.

Unencumbered & Second Story Work

Strength (study for DC).

Superhuman Climb

Encumbered or no Second Story Work

No chance.

Unencumbered & Second Story Work

Strength (study for DC).

Climbing on a Giant or other monster

No route studying needed.

For the initial climb, "strexterity" vs their dexterity. (They are trying to shake you off.) One you're up there, "strexterity" vs their strength to stay on there. (They are trying to scrape you off or knock you off.)

Vice versa when tiny creatures climb on you.

Studying

Unencumbered

Six seconds or less: DC 20 with disad
One minute or less: DC 20
10 minutes or less: DC 15
1 hour or less: DC 10
More than 1 hour: DC 5

(Memory trick: Limits are at 1 round, 10 rounds, 100 rounds, 1 hour, and you need to go strictly longer than the limit to go to the next difficulty class.)

You can only study what you have light. If you come to a dark patch you need to re-light it so you can study more and make a new roll.

Why are the DCs the same even for harder routes? Don't worry about it being too easy, even though the DC is the same, the consequences are more dangerous.

Encumbered

Encumbered adds 5 to DC. Heavy encumbered instead adds 10 to DC. This is only for abseiling or sloped climbs, harder climbs you can't be encumbered.

DC capped routes

Some routes have a minimum DC that you can't go under. You'll know as soon as you hit it.

For example if there's a DC 15 wall. You would see as soon as you had studied it for more than one minute that there is no way to climb it easier than 15 and wouldn't have to waste more time studying it. (Because the DM will tell you.)

These come from modules (Tomb of A have some routes like this), never from the natural veins.

Spider Climb spell, or monster with Climbing speed

Don't worry you can easily traverse any of these w/o rolling, except climbing on a Giant or other monster.