This is the 3795th most frequent Arabic word.
الصيفي
"Al-Sayfi" (الصيفي) means "summer-related" or "summery."
الصيفي is used here as an adjective describing الجو (atmosphere), indicating it pertains to the summer season.
أنا أحب الجو الصيفي في البحر.
I love the summer atmosphere at the sea.
الصيفية is used here as an adjective describing الملابس (clothes), indicating they are suitable for or designed for summer.
ساشتري ملابسا صيفية جديدة هذا الأسبوع.
I will buy new summer clothes this week.
الصيفي is used here as an adjective describing المخيم (camp), indicating the camp takes place in the summer period.