Gwaeron Windstrom is listed as a Forgotten Realms God of Tracking in D&D 5e Sword Coast Adventurer's Guide. However on page 134 he is said to sleep in a grove near the town of Triboar. I'm wondering if this means he is more of a demigod? He clearly lives on the mortal plane and is somewhat of a messenger or liaison to Mielikki, Goddess of Forests.
The DMG (p.11) has the following to say on demigods & lesser deities (italics are my added emphasis):
Lesser deities are embodied somewhere in the planes. Some lesser deities live in the Material Plane, as does the unicorn-goddess Lurue of the Forgotten Realms and the titanic shark-god Sekolah revered by the sahuagin. Others live on the Outer Planes, as Lolth does in the Abyss. Such deities can be encountered by mortals.
Quasi-deities have a divine origin, but they don't hear or answer prayers, grant spells to clerics, or control aspects of mortal life. They are still immensely powerful beings, and in theory they could ascend to godhood if they amassed enough worshipers. Quasi-deities fall into three subcategories: demigods, titans, and vestiges.
Demigods are born from the union of a deity and a mortal being. They have some divine attributes, but their mortal parentage makes them the weakest quasi-deities.
Given the above, that the blurb on Gwaeron Windstrom on SCAG p.134 mentioned in the question describes rangers praying to him as a proxy for Mielikki, and that he is present on the Faerûnian Pantheon list (with domains), I believe it puts him firmly in the lesser deity camp rather than the demigod one.
If he was a demigod in prior editions (as another answer indicates), it's possible that either he gained enough worshipers to ascend to godhood or the definition between demigod & god changed sufficiently between editions that he falls on the other side of the fence now.