Most of the time, eczema is at its worst in the winter. Yet in some cases in hot weather when the body temperatures soar, eczema may be worse for certain people. There are several reasons for this. In some cases, eczema can be made worse by ultraviolet light. Usually this is not the case, but a small number of patients will experience flaring of their eczema when exposed to ultraviolet light through any source, particularly sunlight.