The interior of a greenhouse can be an uncomfortable place in bright summer weather unless the right measures are taken. From now on, the vents can generally be kept open unless it is wet or windy. If a warm spell comes on, prop the door open to generate a flow of cool air.
Keep the temperature down by shading, perhaps with netting hung inside, although tomatoes should never be shaded. Raise humidity by sloshing the floor twice daily with water. These measures will also discourage the dreaded red spider mite.