Despite previous rumors speculating that Apple would be releasing its next generation tablets this month, supply chain sources are pretty certain that iPad 5 production will be starting off towards the middle-end of summer. As noted by DigiTimes:
Volume production of the fifth-generation 9.7-inch iPad will kick off in July-August 2013, according to sources with Taiwan-based supply chain makers. Yield rates for key components, especially touch panels, will be a major concern for smooth production.
In terms of features, we’re expecting the same resolution display panel as the current iPad with Retina, but Apple will undoubtedly boost it by including a more powerful processor and GPU. It’s possible the display unit will be slimmer too if it adopts the same in-cell touch sensors used in the iPhone 5. Design-wise it’ll more than likely use the same design language as the iPad mini; slimmer bezels, anodized aluminum chassis and chamfered edges.
If production does kick off in July or August, that would typically indicate a launch and release some time in September or October.