Hilton Head Island experiences mild winters, with average temperatures ranging from around 11°C in January to 12°C in February. Spring brings gradual warming, with March and April averaging around 16°C and 19°C respectively. Summer months are warm, with July and August averaging 27°C, while September and October see a slight cooldown. Winters can be cool, with temperatures occasionally dipping below freezing in December and January, but overall the island enjoys mild conditions year-round.