Hello Cody Fendant,

Fellow Monks have provided you with the answer to your question. I would like to add another option here with one of my favorite modules regarding time manipulations Date::Manip.

Small sample of code with different timezone(s) and time subtraction. You can apply the time subtraction based on your time of receiving the email etc...

#!/usr/bin/perl
use strict;
use warnings;
use Date::Manip;
use feature 'say';

my $tz = new Date::Manip::TZ;
my $dateLocal = ParseDate('now');
say $dateLocal;

# From timeZone To timeZone
my $dateTimeZone = Date_ConvTZ($dateLocal,"GMT","CST");

my $unixLocal = UnixDate($dateLocal,'%Y-%m-%d-%H-%M-%S');
say 'Local Timezone: ' . $unixLocal;

my $unixTimeZone = UnixDate($dateTimeZone,'%Y-%m-%d-%H-%M-%S');
say 'Different Timezone: ' . $unixTimeZone;

my $date1 = ParseDate($dateLocal);
my $date2 = ParseDate($dateTimeZone);

my $delta = DateCalc($date1, $date2, 1);
say 'Difference between Timezones: ' . $delta;

# Change Format
my $str = UnixDate($dateLocal,"It is now %T on %b %e, %Y.");
say $str;

my $str_second = UnixDate($dateLocal,"It is now %T on %B %e, %Y.");
say $str_second;

my $str_decimal = UnixDate($dateLocal,"It is now decimal %T on %B %d, 
+%Y.");
say $str_decimal;

# Add more time or subtract or do what ever you want with time
my $deltastr = "12 hours ago";

my $date_past = DateCalc($dateLocal,$deltastr);
# say $date;

my $str_past = UnixDate($date_past,"It was 12 hours ago %T on %B %d, %
+Y.");
say $str_past;

__END__

$ perl test.pl
2017110109:11:31
Local Timezone: 2017-11-01-09-11-31
Different Timezone: 2017-11-01-17-11-31
Difference between Timezones: 0:0:0:0:8:0:0
It is now 09:11:31 on Nov  1, 2017.
It is now 09:11:31 on November  1, 2017.
It is now decimal 09:11:31 on November 01, 2017.
It was 12 hours ago 21:11:31 on October 31, 2017.
[download]

Hope this helps, BR.