Aren Maeir has been dropping hints along the way but as the season wraps up, he is more certain.  He writes:

The first [photo] is a working view of the structure which I believe we can now firmly claim to be a temple! The structure, which has at its center two large pillar bases, and some of the exterior walls, had various cult related objects found in its vicinity.

The Jerusalem Post picks up the story and explains some of the biblical significance:

Prof. Aren Maeir, of Bar-Ilan University’s Martin (Szusz) Department of Land of Israel Studies and Archaeology, said on Wednesday that the temple may shed light on the architecture in Philistia at the time when Jewish hero Samson purportedly brought the temple of Dagon down upon himself.
Maier said the architecture of the Philistine temple, the first ever found at Gath, sheds light on what the temple of Dagon would have looked like, in particular the two pillars that anchored the center of the structure.

The story is also reported in Arutz-7.

How do they know that this is a temple and not a house or a shop?  If you’ve ever wondered how archaeologists make such determinations, I highly recommend that you read this morning’s brief post by Maeir in which he explains what they didn’t find as well as what they did.