A Django MultiValue form field that handles a text datetime input and a pytz timezone input from a select list. Also, widget classes and data-format attribute are intended for use with bootstrap-datetimepicker from https://github.com/tarruda/bootstrap-datetimepicker

django_multivalue_datetime_timezone.py

from django import forms
from django.forms.fields import MultiValueField
 
import pytz
 
# provided by django-timezone-field==0.4
from timezone_field import TimeZoneFormField
 
 
class DatetimeTZWidget(forms.MultiWidget):
  """
    A widget that splits splits a datetime text entry and a timezone select list.
	"""
 
	def __init__(self):
		widgets = (
			forms.DateTimeInput(
				format='%m/%d/%Y %I:%M %p',
				attrs={'class':'input-medium datepicker', "data-format": "MM/dd/yyyy HH:mm PP"}
			),
			forms.Select(choices=TimeZoneFormField().choices)
		)
		super(DatetimeTZWidget, self).__init__(widgets)
 
	def decompress(self, value):
		if value:
			return value.rsplit(" ", 1)
		return ["", ""]
 
	def format_output(self, rendered_widgets):
		return u'%s %s' % (rendered_widgets[0], rendered_widgets[1])
 
 
class DatetimeTZField(MultiValueField):
	widget = DatetimeTZWidget
 
	def __init__(self, *args, **kwargs):
		errors = self.default_error_messages.copy()
		if 'error_messages' in kwargs:
			errors.update(kwargs['error_messages'])
		fields = (
			forms.DateTimeField(input_formats=['%m/%d/%Y %I:%M %p']),
			TimeZoneFormField(),
		)
		super(DatetimeTZField, self).__init__(fields, *args, **kwargs)
 
	def compress(self, data_list):
		if data_list:
			# first make the datetime they entered tz aware
			_date = data_list[1].localize(data_list[0])
			# then convert to UTC for storage
			return _date.astimezone(pytz.timezone('UTC'))
		return None