Condensation forms on the windows, doors, and even the walls of a room when the temperature outside is colder and has a lower relative humidity than the interior. It is created when water vapor or humidity is converted from gas to liquid while there is a sudden drop in temperature at the surface it interacts with.
Most people automatically think condensation is something to worry about solely in the winter, but it can occur year round. Your bathroom, kitchen, laundry room, and any other room where there is an excess of steaming or boiling water can fall victim to condensation at any time of year. Since plants are constantly releasing water vapor, having an abundance of indoor plants will also increase condensation; this means that condensation is also commonly found in greenhouses and garden windows.
Structures with high efficiency window systems may regularly experience condensation. The tight seals on their windows and doors may prevent the outside weather from entering, but they are also trapping the humid air inside the structure. Simple ways to manage the condensation in your structure include increasing air circulation by fans or vents, using a dehumidifier, or eliminating the water source altogether.