c. 1300, "a period of the year," with reference to weather or work, also "proper time, suitable occasion," from Old French seison, also saison "season, date; right moment, appropriate time" (Modern French saison) "a sowing, planting," from Latin sationem (nominative satio) "a sowing, planting," noun of action from past participle stem of serere "to sow" (from PIE root *sē- "to sow").
Sense shifted in Vulgar Latin from "act of sowing" to "time of sowing," especially "spring, regarded as the chief sowing season." In Old Provençal and Old French (and thus in English), this was extended to "season" in general. In other Indo-European languages, generic "season" (of the year) words typically are from words for "time," sometimes with a word for "year" (as in Latin tempus (anni), German Jahreszeit). Of game (as in out of season) from late 14c. Spanish estacion, Italian stagione are unrelated, being from Latin statio "station."
Meaning "time of year during which a place is most frequented" is from 1705. Season ticket is attested from 1820.
Old English sawan "to scatter seed upon the ground or plant it in the earth, disseminate" (class VII strong verb; past tense seow, past participle sawen), from Proto-Germanic *sean (source also of Old Norse sa, Old Saxon saian, Middle Dutch sayen, Dutch zaaien, Old High German sawen, German säen, Gothic saian), from PIE root *sē- "to sow," source of semen, season (n.), seed (n.). Figurative sense was in Old English.
Proto-Indo-European root meaning "to sow."
It is the hypothetical source of/evidence for its existence is provided by: Latin serere "to sow;" Old Church Slavonic sejo, sejati; Lithuanian sju, sti "to sow;" Old English sawan "to sow;" Old Prussian semen "seed," Lithuanian smenys "seed of flax," Old Church Slavonic seme, Old High German samo, German Same;Old English sed, sd "that which may be sown; an individual grain of seed."