。
It will probably rain in the evening.
Literal
Evening-time [at-には] probably rain become-[conjectural-だろう].
夕刻 ('evening, dusk') is a formal-literary word, more elegant than 夕方 and common in written forecasts or narratives. おそらく ('probably, likely') is the higher-register equivalent of たぶん. だろう ('probably') is the plain conjectural. The three together give the sentence a dry, written/newscast flavor.