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