The butterflies roost at night in long grass or shrubs. They also seek shelter in windy, cold, or cloudy weather. A butterfly house is an interesting addition to the garden, but there's no guarantee the butterflies will use it. Sunlight is important, since butterflies need temperatures over 60 degrees or they can't fly. Large rocks in the butterfly garden store heat for a long time, and you will see the butterflies sitting there soaking up the warmth.
Female butterflies choose host plants in bright sun forlaying eggs.
Butterflies get water from wet sites. They feed on the moisture in the earth surrounding puddles, and get some of their nutrients from the dirty water. A pond or stream in your garden will help in attracting butterflies. Lacking this, regular garden watering or a drip line will provide them with enough soaked soil for their needs. If you decide to make a butterfly garden, start now.