Poinsettias should not stay outside in temperatures that are below 60 degrees Fahrenheit. When the plants are moved outdoors in warm weather, they should be placed in a partially shaded location for the first 2 weeks and then moved to an area that receives full sun.
Poinsettias that are kept inside should be in a place that is between 65 and 70 degrees Fahrenheit during the day. An ideal location is a window that provides bright, indirect light, although the leaves should not touch the window. Poinsettias go dormant in the winter if they receive little water and are stored in a location that is below 60 degrees Fahrenheit.