雨が夜通し降り続いた。
The rain continued throughout the night.
一晩 simply names one night as a unit of time, whereas 夜通し is an adverb meaning 'all through the night', stressing continuous, unbroken action.
Standard kanji spelling; high frequency in news and written Japanese.
Mixed kanji-kana spelling; less common but still encountered.
Compound of 夜 (yo, 'night') + 通し (tōshi, 'through, continuously'), from the verb 通す (tōsu, 'to let pass through').