Every language has unique linguistic items that lack straightforward linguistic counterparts in other languages i.e. not lexicalized in the source language. This paper investigates the distribution (re- presentation) of unique items in the translated texts from English into Arabic depending on the hypothesis of Unique Items suggested by (Tirkkonene-Condit 2002) which is one of the so-called translation universal hypotheses. This hypothesis is adopted to predict the frequencies of the unique items of the target language in the translated texts (over or under representations) namely the lexical items of rain such as: , , , , , which are respectively represented in English by two kinds of occurrences, single words as drizzle, wet, shower, deluge, downpour, torrents and mansoon , and phrases such as trickling rain, sputtering rain or it's pouring down and so on . Translators' behavior is measured according to Toury's law of interference. The results reveal that even the English source text doesn't present any translation difficulty, the unique Arabic items are less frequent and under-represented in translated texts compared to original Arabic texts. Also, the study finds that the translators tend to use general solutions in translating unique items of rain, besides a clear interference of the source text is discovered in the translators' preferences.