Heliocentrism isn't the only theory that implies the existence of the seasons:

The motion of the sun eastward along the ecliptic combined with the rotation of the stars westward along the equator to account for seasonal changes in the length of daylight, while moving the circle of the sun's motion slightly off-center toward Gemini adjusted for the inequality of the seasons. The resulting extremes of apogee and perigee of the sun also explained for writers on the sphere why the arctic regions are too cold, and the southern hemisphere is too hot, to be habitable; the intermediate region of habitation was divided into seven climes according to half-hour differences in the length of the solstitial day. Yet another very slow motion of the celestial sphere about the poles of the ecliptic produced the gradual drift, or precession, of the equinoctial and solstitial points eastward along the zodiac; in some accounts, e.g. Robert Grosseteste's (ca. 1215-1230), this Ptolemaic device was supplanted by Thâbit b. Qurra's more intricate mechanism for non-uniform precession, or trepidation.

-- M. S. Mahoney, Dictionary of the Middle Ages