This is the 6401st most frequent Arabic word.
احيانا
Sometimes.
Here, 'أحياناً' is used to indicate that the action of going to the library happens on certain occasions but not regularly.
أحياناً أذهب إلى المكتبة لأقرأ بعض الكتب.
Sometimes I go to the library to read some books.
In this sentence, 'أحياناً' expresses irregular occurrences of cloudy skies during the summer season.
السماء أحياناً تكون غائمة في الصيف.
The sky is sometimes cloudy in summer.
The word 'أحياناً' here shows that the activity of watching movies with the family is done occasionally, depending on the circumstances.