IT can, and does, operate within a wide humidity range. Seasonal humidity changes are usually easier to control than hourly fluctuations. Under either circumstance, normally the primary environmental concern is preventing conditions that permit humidity alterations where condensation is the result. Data culled from analysis of historical psychrometer reading can be instrumental in determining seasonal changes or outside influences. Technically, a psychrometer is a hydrometer consisting of two thermometers with bulbs, one wet and one dry. One bulb is kept wet so the cooling that results from evaporation permits registration of a lower temperature than the dry bulb. The difference between the two readings constitutes a measure of atmospheric dryness.
“View Part I of the Hardware Protection… Dust, Temperature, and Humidity – Oh My! series here“