from django.utils import timezone
 def timezone_processor(request):
     # look for a cookie that we expect to have the timezone
     tz = request.COOKIES.get('local_timezone', None)
     if tz:
         tz_int = int(tz) # cast to int
         # here we decide what will prefix timezone number
         # the output of tz_str will be something like: 
         #                Etc/GMT+1, GMT+0, Etc/GMT-2
         if tz_int >= 0:
             tz_str = 'Etc/GMT+'+tz
         else:
             tz_str = 'Etc/GMT'+tz
         # this forces timezone
         timezone.activate(tz_str)
     # Now we tell the template that we have a timezone
     return {'local_timezone': tz}
 

 TEMPLATES = [
     {
         .........
         'OPTIONS': {
             'context_processors': [
                 .........
                 'myapp.context_processors.timezone_processor',
             ],
         },
 

 <!-- if django already knows timezone we will not run it again -->
 {% if not local_timezone %}
     <!-- getTimezoneOffset does the trick! -->
     <!-- it return minutes so we divide to get hours -->
     timezone = new Date().getTimezoneOffset() / 60;
     document.cookie = 'local_timezone=" + timezone;
     <!-- set a cookie with this value and we are done -->
 {% endif %}