@smpotter's script does require WIFI to be on. The autotimezone.sh script referenced above doesn't base your time on location, its a static location. Here's the JAMF code he's referencing:
#!/bin/sh
####################################################################################################
#
# Copyright (c) 2010, JAMF Software, LLC. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# * Neither the name of the JAMF Software, LLC nor the
# names of its contributors may be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY JAMF SOFTWARE, LLC "AS IS" AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL JAMF SOFTWARE, LLC BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
####################################################################################################
#
# SUPPORT FOR THIS PROGRAM
#
# This program is distributed "as is" by JAMF Software, LLC's Resource Kit team. For more
# information or support for the Resource Kit, please utilize the following resources:
#
# http://list.jamfsoftware.com/mailman/listinfo/resourcekit
#
# http://www.jamfsoftware.com/support/resource-kit
#
# Please reference our SLA for information regarding support of this application:
#
# http://www.jamfsoftware.com/support/resource-kit-sla
#
####################################################################################################
#
# ABOUT THIS PROGRAM
#
# NAME
# setTimeZone.sh -- Set the time zone
#
# SYNOPSIS
# sudo setTimeZone.sh
# sudo setTimeZone.sh <mountPoint> <computerName> <currentUsername> <timeZone>
#
# If the $timeZone parameter is specified (parameter 4), this is the time sone that will be set.
#
# If no parameter is specified for parameter 4, the hardcoded value in the script will be used.
#
# DESCRIPTION
# This script sets the system time zone as reflected in the Date & Time preference pane with the
# System Preferences application. It has been designed to work on Mac OS X 10.3 and higher.
#
# A list of supported time zone entries can be found by running the command:
#
# For Mac OS X 10.5 or later:
#
# /usr/sbin/systemsetup -listtimezones
#
# For Mac OS X 10.4 or earlier:
#
# /System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/systemsetup -listtimezones
#
# The system time zone will be set according to the value specified in the paramter $timeZone.
# It can be used with a hardcoded value in the script, or read in as a parameter. Since the
# Casper Suite defines the first three parameters as (1) Mount Point, (2) Computer Name and
# (3) username, we are using the forth parameter ($4) as the passable parameter. If no parameter
# is passed, then the hardcoded value will be used.
#
####################################################################################################
#
# HISTORY
#
# Version: 1.0
#
# - Created by Nick Amundsen on August 5th, 2008
#
# Version: 2.0
#
# - Updated by Brock Walters October 28 2014
#
####################################################################################################
#
# DEFINE VARIABLES & READ IN PARAMETERS
#
####################################################################################################
#
# A HARDCODED VALUE FOR "timeZone" CAN BE SET BELOW.
#
# A list of accepted time zone values can be generated using the following command in Terminal:
#
# sudo systemsetup -listtimezones
#
# Delete the double quotes and replace with the desired time zone name, e.g. timeZone=Pacific/Honolulu
# If this script is to be deployed via policy using the JSS leave the next line as is.
#
####################################################################################################
timeZone=""
####################################################################################################
#
# SCRIPT CONTENTS - DO NOT MODIFY BELOW THIS LINE
#
####################################################################################################
# CHECK TO SEE IF A VALUE WAS PASSED IN PARAMETER 4 AND, IF SO, ASSIGN TO "timeZone"
if [ "$4" != "" ] && [ "$timeZone" == "" ]
then
timeZone=$4
fi
osx=$(/usr/bin/defaults read /System/Library/CoreServices/SystemVersion ProductVersion)
maj=$(/usr/bin/defaults read /System/Library/CoreServices/SystemVersion ProductVersion | awk '{print substr($1,1,2)}')
ref=$(/usr/bin/defaults read /System/Library/CoreServices/SystemVersion ProductVersion | awk '{print substr($1,4,2)}')
if [ $maj -gt 10 ]
then
echo
echo "Check OS string format & OS X systemsetup utility for script compatibility with OS X version $osx"
echo
exit
fi
if [ "$timeZone" != "" ]
then
if [ $ref -lt 5 ]
then
echo
echo "Setting time zone for OS X $osx..."
/System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/systemsetup -settimezone "$timeZone"
/usr/bin/killall SystemUIServer
echo "Refreshing the clock in the Menu Bar..."
echo
else
echo
echo "Setting time zone for OS X $osx..."
/usr/sbin/systemsetup -settimezone "$timeZone"
/usr/bin/killall SystemUIServer
echo "Refreshing the clock in the Menu Bar..."
echo
fi
else
echo
echo "Error: The timeZone variable is not populated. Press the return key "
echo "to generate a list of valid time zones. Select & copy the desired "
echo "time zone from the list & paste into the script on the line reading "
echo
echo " timeZone="" "
echo
read -p ""
/usr/sbin/systemsetup listtimezones
exit
fi
