The percentage of moisture in air relative to the maximum it can hold at that temperature.
Typical use
Use this measurement as part of a trend or comparison. Location, instrument, time and environmental condition should be recorded with the value.
Unit and context
Common unit: % RH. A number without context can be misleading.
What it does not prove
A measurement supports an investigation; it does not automatically identify the source, duration or hidden extent of a problem.
Observe→Distinguish→Control source→Verify
Living dossierPublished knowledge is connected and improved as new cases, images and outcomes are added. Updated 2026-07-20.
