Temperature and Humidity in the OR
The ambient temperature of the OR often represents a compromise between the needs of the patient and those of the staff; the temperature desired by staff itself is a compromise between the needs of personnel who are dressed in surgical gowns and those who are not. OR temperatures range from 18º to 26º C (64.4º to 78.8º F).
A higher temperature is necessary during operations on infants and burn patients because conservation of body heat is critical in these patients. Generally, surgeons who are actively working and fully gowned prefer a temperature of 18º C (64.4º F), but anesthesiologists prefer 21.5º C (70.7º F).[14]

Humidity in the OR is generally maintained at between 45% and 60%; humidity greater than 60% may cause condensation on cool surfaces and more importantly microbial growth.

Hazardous Microbiological Growth
Many bacteria flourish in humid air. According to a study done by Pennsylvania State University, the bacteria responsible for Legionnaire’s disease (Legionella pneumophila) survive best at a Relative Humidity of
65%. Many viruses also thrive in high humidity. The Polio virus not only survives, but multiplies when air is above 80% RH. Fungi and dust mites also thrive in humid building materials, which can lead to musty odors and respiratory problems associated with sick building syndrome. The high humidity in ductwork downstream for cooling coils is, unfortunately, an ideal environment for these organisms.