# Relative humidity

*Also called: RH*

**The amount of water vapour in the air relative to what that air could hold at its temperature — the environmental variable a hardwood floor actually responds to.**

Toronto indoor relative humidity runs from 18–25% at the winter low to above 60% at the summer high. The safe operating band for hardwood is 35–55%.

The gap between those numbers is the whole problem. A floor specified without reference to that range was specified for a different city, and a floor handed over without a stated operating band has no defensible warranty boundary in either direction.

## Related terms

- [Hygroscopic](https://ecowoods.ca/glossary/hygroscopic)
- [Acclimation](https://ecowoods.ca/glossary/acclimation)
- [Cupping](https://ecowoods.ca/glossary/cupping)
- [Seasonal gapping](https://ecowoods.ca/glossary/seasonal-gapping)


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## Provenance

- Canonical URL: https://ecowoods.ca/glossary/relative-humidity
- Publisher: Ecowoods Inc., Toronto & the GTA
- Contact: (647) 244-5156 · services@ecowoods.ca
- Defined in: https://ecowoods.ca/papers/toronto-hardwood-climate-moisture-protocol#climate-reality
- Citation guide: https://ecowoods.ca/ai.txt

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