Frost's meaning is revealed in the last two couplets of the aabb ccdd eeff gg rhyme scheme sonnet having two voltas (line 5 and 9) and a paradoxical resolution in the last couplet. There are varying critical discussions about the particulars of this poem, yet all agree that the ending points to a universal meaning of a spiritual malevolence--a dark intention--assaulting Earth and Earth's people. Not all agree, however, that the poem has meaning derived from Frost's childhood fear of the Pacific Ocean. Whether Frost's childhood fear inspired the poem of impending disaster or just provided the fodder for the inspired vision of universal application is unknown but not necessary to an understanding of personification's impact on it meaning.
The entire poem is personification. When nature is personified in this way, poetic convention often refers to it as a pathetic fallacy, a much later term than "personification" and a specialized subcategory of personification.
The water acts so as to make: "water made a din."
The waves look intending to see: "waves looked over others."
The waves have thoughts of grandeur and destruction: "thought of doing ... [what water] never did before."
The clouds have personalities: "clouds were low and hairy ... [with] gleam of eyes."
The shore and cliff were "lucky" they were supported by the whole "continent."
The night had "dark intent," which signifies volition and intention.
Humans ("Someone") need to be prepared for this personified "rage" of ocean and sky.
The personified ocean and sky would act so as to do great harm before God closed the final chapter of Earth's existence.
Rather than say personification "contributes to the meaning" it is more accurate to say personification embodies the meaning of the poem, and that meaning seems to be a prophetic one. Did Frost truly have a visionary inspiration--did he really see into the stormy future of the following centuries, because they have been stormy and may get stormier soon. Or did Frost feel inspired by the apt application of his childhood terror to the end times scenario foretold in Revelations of the Bible?
Either way, the meaning of the poem is that the physical world will rise up and wreak destruction on planet and human. Much harm will be done before Earth gives way its existence in the finale of its story. God may or may not play an overseeing role in the events told of. It seems most likely, though, that God enters the paradoxical resolution unaware and solely to say, "Ok, the end time has come," and to tell nature to "Put out the light," only to find the paradox that ocean and sky have left little behind to put the light out on.