Humidity
There is no single number for "correct reptile humidity" — a desert bearded dragon and a tropical crested gecko need close to opposite conditions.
Key facts
- Humidity too low causes shedding (ecdysis) problems; too high with poor ventilation raises fungal and respiratory risk.
- Desert species (bearded dragon) commonly want around 30-40% by day, up to 50-55% at night; tropical species (crested gecko) are meant to swing between roughly 45-50% and 80%+, not sit at one fixed number.
- These two examples show there is no single "reptile humidity" figure — it is set by the specific species.
Why humidity matters at all
Humidity that's too low is linked to shedding (ecdysis) problems — skin that doesn't come off cleanly, with pieces left stuck. Humidity that's too high combined with poor ventilation raises the risk of fungal, bacterial and respiratory problems. The goal is not "maximum humidity" but the level a given species actually needs, with enough ventilation to go with it.
The species-to-species spread, in real numbers
For bearded dragons (a desert species), daytime humidity of roughly 30-40% is commonly recommended, with a rise to 50-55% at night considered acceptable — indoor humidity naturally climbs overnight anyway. Persistently high humidity is linked to fungal and bacterial risk more strongly than mild low humidity is.
For crested geckos (a tropical species), humidity is meant to fluctuate rather than sit still: misting pushes it to 80%+ (holding around 60-80% overnight), then it's allowed to dry down to roughly 45-50% before the next misting — a wet-then-dry cycle, not one constant value.
These two figures directly contradict each other if you try to reduce them to one "reptile humidity" number — which is exactly the proof that the right target always comes from the specific species.
Controlling humidity in practice
- Manual misting or an automated fogging/misting system.
- Humid hides — raise humidity locally where needed, without changing the whole terrarium.
- Substrate choice — moisture-retentive or quick-drying (see the choosing-a-substrate guide).
- Ventilation — controls how fast the terrarium dries out after misting.
- Live plants — help maintain local humidity.
Measuring it
A hygrometer is best placed near the level where the animal actually spends its time, not just at the top vent of the terrarium — we could not find a solid source on exact placement accuracy, so treat this as general good practice rather than a cited figure.