Polyhouse is a framed or inflated structure covered with transparent or translucent polythene papers, large enough to grow crops under partial or fully controlled environmental conditions to get optimum growth and productivity. However, the roof of the polyhouse reduced photosynthetically active radiation about 39% compared to outside. Air and soil temperatures were always higher inside the polyhouse though relative humidity showed opposite trends with that of air temperature. Flowering and fruit setting in polyhouse plants were advanced by about 3 and 4 days, respectively compared to open field condition. Similarly, tomato plants grown under polyhouse showed the best performance in terms of vegetative development, reproductive development, yield contributing characters and yield over open field condition. The fruit yield obtained from the polyhouse was about 29% higher than open space due to optimum temperature and low relative humidity suitable for tomato production in polyhouse. In addition, heavy rainfall and hail storm during late winter (March) decreased the yield of tomato in open field, but in that situation polyhouse protected the plants from damage caused by hail storm.