Since you only want hour granularity just divide the epoch time by the number of seconds in an hour: 
my %date_count;

foreach my $time ( @times ) {
    $date_count{ ( $time / 3600 ) * 3600 }++;
}

[download]
Then later you can break it down into years/months/days/hours.

In reply to Re: Split date ranges/chunks based on Unix epoch time? by jwkrahn
in thread Split date ranges/chunks based on Unix epoch time? by Anonymous Monk

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