Behind closed drapes, the temperature of the air around the plant drops rapidly. When the outside temperature is very low, and its windy, the window sill temperature can get low enough to cause chilling injury. Chilling injury can occur when the temperature is as high as 45 degrees. Plants susceptible chilling injury will not recover if long exposure to low temperatures. When the temperature of the glass is below freezing, plant parts actually in contact with the glass, will be frosted.
High temperatures are also a problem.
The most common symptom is wilting. If the temperature is high enough, plants growing in moist soil will wilt. This may lead inexperienced gardeners to over-water a plant wilted due to high temperatures. The leaves exposed to sunlight may be several degrees warmer than the surrounding air. In this instance the high temperature problem is internal to the plant.