THESAURUS
seasonal
aestival, alternate, arctic, autumn, autumnal, beating, boreal, brumal, canicular, circling, cyclic, epochal, equinoctial, even, every other, hibernal, hiemal, intermittent, isochronal, measured, metronomic, midsummer, midwinter, oscillatory, out of season, periodical, pulsing, reciprocal, recurrent, recurring, rhythmic, rotary, serial, solstitial, spring, springlike, steady, summer, summerlike, summerly, summery, undulant, undulatory, vernal, wavelike, wheeling, winter, winterlike, wintery, wintry