As long as they are kept indoors, peace lilies do not require any special care during the winter. They do not enter a dormant phase in colder months as some other plants do. Fertilizer is not necessary during the winter, and the plants may require slightly less water.
The popularity of peace lilies as houseplants is partly attributable to their resilience. They fare best in indoor temperatures that are also comfortable for humans, specifically in the range of 65 to 80 degrees Fahrenheit. Frost or temperatures lower than 45 degrees Fahrenheit may kill peace lilies. They are also sensitive to drastic temperature changes, so it is best not to transport them through chilly outdoor weather if at all possible.
Peace lilies do not bloom in the winter. Their lovely white blooms appear in spring and early summer and continue for several months. They thrive in the shade with a bit of indirect light. Yellowing leaves or brown spots indicate they are receiving more light than they need. To encourage flowers to bloom, move the peace lily to a darker space. Peace lilies can be moved outdoors in warmer months, but must be returned indoors before temperatures fall or begin to fluctuate too drastically.