Good quality light is important to the growth of an orchid. However, protect your plants from direct sunlight during the middle part of the day and during the summer when light and heat are both greater.
Perfect growth balance for orchids is determined between the plant, the light it receives, the nutrients it absorbs and the temperature of air in which it is kept.
Orchids grow best at 60 and 85 degrees F. In other words, grow orchids in temperatures in which you, yourself, are comfortable.
Cold slows down growth and the leaves become brittle and consistently high temperatures can cause rapid, weak, immature growth.