Free tables Natural 20 — skill checks

Natural 20 Table — Nature Skill Checks, d20

A free d20 table for a natural 20 on a Nature check in 5e. Twenty outcomes, from solid to legendary.

A natural 20 on a skill check is not a critical success in fifth edition — criticals apply to attack rolls only, and a 20 on a check is simply a 20. Which is why a legendary roll so often feels like nothing happened. This table gives it somewhere to land.

Twenty results written for Nature specifically. A legendary Nature roll has nothing in common with a legendary roll at anything else, which is why there are eighteen of these and not one.

Roll d20 when a player rolls a natural 20 on a skill check and succeeding quietly would be a waste.

Severity tiers

Each result names its tier, so you can see at a glance how bad a roll was without decoding a colour.

Solid 1–10 — Cleanly done, with something small to show for it.
Impressive 11–17 — Better than anyone expected. Momentum, or an obstacle gone.
Legendary 18–20 — Scene-shaping. The kind of success people repeat afterwards.

The table

20 results. Roll d20.

d20	Result	Tier	What happens
1	Knew the Species	Solid	You identify the creature or plant exactly, including one weakness. No extra effect.
2	Safe to Eat	Solid	You find food and water enough for the party for a day, and it is genuinely safe.
3	Read the Weather	Solid	You know what the sky is going to do for the next day, and how to use it.
4	Useful Reagent	Solid	You spot a component or herb worth harvesting here, and know how.
5	Not Its Territory	Solid	You determine that whatever lives here is not native, which raises a useful question.
6	Their Habits	Solid	You know when the local creatures feed, sleep, and hunt. Plan accordingly.
7	Attuned	Solid	You have advantage on your next Nature or Survival check this scene.
8	Safe Ground	Solid	You identify where it is safe to camp, cross, or shelter here.
9	Told the Party	Solid	Every ally has advantage on their first saving throw against this environment or creature type.
10	The Antidote Grows Here	Solid	Whatever the local hazard is, the remedy for it is within reach.
11	Read the Whole System	Impressive	You understand what's wrong with this place ecologically — and therefore what caused it.
12	Avoided Entirely	Impressive	You know how to move through here without provoking the local wildlife at all.
13	Harvested Well	Impressive	You gather enough reagent, venom, or material for several uses, not one.
14	The Beast's Weakness	Impressive	You learn a specific, exploitable vulnerability. The DM should make it mechanically real.
15	Shortcut	Impressive	You find a route through the terrain that saves the party significant time or danger.
16	Predicted It	Impressive	You know what the environment is about to do — the flood, the collapse, the migration — before it happens.
17	Made It Yours	Impressive	You can use the terrain deliberately in the coming encounter. The DM grants one concrete advantage from it.
18	Named the Cause	Legendary	You identify what is truly wrong with this land, and it is not what anyone assumed. The DM gives you the real answer.
19	The Land Cooperates	Legendary	For the rest of this scene the environment works in the party's favour — terrain, weather, and wildlife all break your way.
20	The One They'll Talk About	Legendary	Your reading of the wild solves a problem the party expected to fight through. The obstacle simply isn't one any more, and the local creatures will remember you kindly.

Questions

Is a natural 20 a critical success on a skill check?

Not by the rules. Criticals apply to attack rolls. A 20 on a check is a 20 — which is why a spectacular roll so often produces a shrug. This table is the house rule that fixes that.

Does a natural 20 automatically succeed?

No. On an ability check there is no automatic success — if the DC is 25 and your total is 22, you failed with a 20.