Museum environmental monitoring is the repeated measurement and review of conditions around collections, such as temperature, relative humidity, light intensity, and, where relevant, CO₂. Time-stamped data helps museums document baseline conditions, identify changes, compare spaces, and make informed preservation and facility decisions.

There is no single temperature or relative humidity setting that is appropriate for every collection. Targets should reflect the materials, their condition and history, the building and enclosure, applicable loan requirements, and guidance from conservation professionals. Monitoring helps teams understand how closely conditions remain within their selected targets and how quickly or frequently they change.

Place data loggers where they represent the conditions objects actually experience, such as inside display cases, in galleries, on storage shelving, in archives, and within transit containers. Avoid placing a logger beside a vent, door, window, heat source, or exterior wall unless that is the condition you intend to investigate. Multiple loggers can reveal differences between rooms, cases, heights, and HVAC zones.

The logging interval should match the questions you're asking, the expected rate of change, the risk to the collection, and the intended deployment length. Shorter intervals can reveal rapid cycles or events, while longer intervals extend the period covered by the logger’s memory. Use consistent intervals when comparing locations, and review data often enough to respond to sustained excursions.