diff --git a/django/db/backends/__init__.py b/django/db/backends/__init__.py
index 7674f5c879..6f1f4b9618 100644
--- a/django/db/backends/__init__.py
+++ b/django/db/backends/__init__.py
@@ -710,6 +710,14 @@ class BaseDatabaseOperations(object):
         """
         raise NotImplementedError
 
+    def set_time_zone_sql(self):
+        """
+        Returns the SQL that will set the connection's time zone.
+
+        Returns '' if the backend doesn't support time zones.
+        """
+        return ''
+
     def sql_flush(self, style, tables, sequences):
         """
         Returns a list of SQL statements required to remove all data from
diff --git a/django/db/backends/postgresql_psycopg2/base.py b/django/db/backends/postgresql_psycopg2/base.py
index 802ebf2b80..0d25129313 100644
--- a/django/db/backends/postgresql_psycopg2/base.py
+++ b/django/db/backends/postgresql_psycopg2/base.py
@@ -190,7 +190,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
                     # Set the time zone in autocommit mode (see #17062)
                     self.connection.set_isolation_level(
                             psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)
-                    self.connection.cursor().execute("SET TIME ZONE %s", [tz])
+                    self.connection.cursor().execute(
+                            self.ops.set_time_zone_sql(), [tz])
             self.connection.set_isolation_level(self.isolation_level)
             self._get_pg_version()
             connection_created.send(sender=self.__class__, connection=self)
diff --git a/django/db/backends/postgresql_psycopg2/operations.py b/django/db/backends/postgresql_psycopg2/operations.py
index 949a05c0b6..395cd92047 100644
--- a/django/db/backends/postgresql_psycopg2/operations.py
+++ b/django/db/backends/postgresql_psycopg2/operations.py
@@ -71,6 +71,9 @@ class DatabaseOperations(BaseDatabaseOperations):
             return name # Quoting once is enough.
         return '"%s"' % name
 
+    def set_time_zone_sql(self):
+        return "SET TIME ZONE %s"
+
     def sql_flush(self, style, tables, sequences):
         if tables:
             # Perform a single SQL 'TRUNCATE x, y, z...;' statement.  It allows
diff --git a/django/test/signals.py b/django/test/signals.py
index d6797395cf..01d55817a2 100644
--- a/django/test/signals.py
+++ b/django/test/signals.py
@@ -1,14 +1,23 @@
 from django.conf import settings
-from django.db import close_connection
+from django.db import connections
 from django.dispatch import Signal
 
 template_rendered = Signal(providing_args=["template", "context"])
 
 setting_changed = Signal(providing_args=["setting", "value"])
 
-# Close the database connection to re-establish it with the proper time zone.
-def close_connection_on_time_zone_change(**kwargs):
-    if (kwargs['setting'] == 'USE_TZ'
-        or (kwargs['setting'] == 'TIME_ZONE' and not settings.USE_TZ)):
-        close_connection()
-setting_changed.connect(close_connection_on_time_zone_change)
+def update_connections_time_zone(**kwargs):
+    if kwargs['setting'] == 'USE_TZ' and settings.TIME_ZONE != 'UTC':
+        USE_TZ, TIME_ZONE = kwargs['value'], settings.TIME_ZONE
+    elif kwargs['setting'] == 'TIME_ZONE' and not settings.USE_TZ:
+        USE_TZ, TIME_ZONE = settings.USE_TZ, kwargs['value']
+    else:   # no need to change the database connnections' time zones
+        return
+
+    tz = 'UTC' if USE_TZ else TIME_ZONE
+    for conn in connections.all():
+        tz_sql = conn.ops.set_time_zone_sql()
+        if tz_sql:
+            conn.cursor().execute(tz_sql, [tz])
+
+setting_changed.connect(update_connections_time_zone)