Frequently opening the refrigerator door creates humidity because it lets warm, humid air enter the unit, making it more difficult for the refrigerator to remove the excess moisture. The moisture can also build up inside a refrigerator when it’s started up after a long period of inactivity.
One way to solve problems related to humidity is to limit exposing the inside of a refrigerator to warm air, particularly during hot seasons. Containers that aren't properly sealed and unwrapped food products that contain a high level of moisture, including lettuce and celery, also negatively affect the humidity levels. The humidity issue caused by the initial start-up typically resolves itself within the first 24 hours after activation once the temperature inside the refrigerator stabilizes.