The present study investigates numerically the effect of solar radiation distribution during the production season at three time-days in arc three span type greenhouse with continuous side vents and a different rows tomato crop orientation using a fluent CFD code. A three dimensional mesh was used to render the geometry of greenhouse's section, and the finite volume method was adopted to carry out the fully elliptic partial differential equations problem. The variation of solar incident radiation at three hours sun of atypical day was incorporated as time dependent condition using solar calculator according to a given position, date and time. Physical and Optical properties of the covering material were defined according to the wave-length of the incoming solar radiation for three spectral areas (UV, PAR and near infrared). Radiative heat transfers were modeled using the three-banded discrete (OD) model, and the culture was considered a porous medium.The results show that the radiation distribution presents symmetrical time behavior and temperature pattern inside the greenhouse is a combination of the convective flow and radiative heat transfer at a three hour sun.