Årstid = Season (år = year, tid = time)
Vår = Spring
Sommar = Summer
Höst = Autumn
Vinter = Winter
Försommar = The beginning of / early summer
Sensommar = Late summer
Förvinter = The beginning of / early winter
Senvinter = Late winter
Midsommar = Mid summer
Brittsommar / indiansommar = Indian summer, the period in autumn, often October, where warm weather returns one last time
Järnnätter = The ice-cold, frosty nights that can still occur late in spring, or early summer
Examples of season-related expressions:
på sommaren / på vintern = in summer / in winter
på våren / på hösten = in spring / in autumn
nästa vår / sommar / höst / vinter = next spring / next summer / next autumn / next winter
förra våren / sommaren / hösten / vintern = last spring / last summer / last autumn / last winter
under våren / sommaren / hösten / vintern = during the spring / during the summer / during the autumn / during the winter
förrförra våren / sommaren / hösten / vintern = two springs ago / two summers ago / two autumns ago / two winters ago
vårdagjämning = vernal equinox
höstdagjämning = autumnal equinox
sommarsolståndet = summer solstice
vintersolståndet = winter solstice
under hela våren / sommaren / hösten / vintern = throughout the whole spring / summer / autumn / winter
sedan september = since September
vårig / somrig / höstig / vintrig = springlike / summery / autumnal / wintry
i våras / somras / höstas / vintras = this past spring / summer / autumn / winter
