Some ORs experience rises in humidity in summer. This APSF free answer to a query discusses the rationale and impact of working outside the generally recommended humidity levels 20 – 60%.
Low humidity could affect shelf life or generate electrostatic sparks. High humidity is uncomfortable for staff and could increase wound infection or cause mildew or mild in the longer term. The evidence on both fronts is sparse but equipment and supplies often specify ranges that prudent organizations adhere to, which may involve suspending operations.