diff --git a/actionpack/test/template/date_helper_test.rb b/actionpack/test/template/date_helper_test.rb
index 3334f4ffb0766836c5a40495efd87e4bd099a0d8..b4eb3f76e1a680db21fa1edadcf3cf2c376b6dd5 100644
--- a/actionpack/test/template/date_helper_test.rb
+++ b/actionpack/test/template/date_helper_test.rb
@@ -1885,7 +1885,7 @@ def test_datetime_select_defaults_to_time_zone_now_when_config_time_zone_is_set
     time = stub(:year => 2004, :month => 6, :day => 15, :hour => 16, :min => 35, :sec => 0)
     time_zone = mock()
     time_zone.expects(:now).returns time
-    Time.zone_default = time_zone
+    Time.zone = time_zone
     @post = Post.new
 
     expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
@@ -1912,7 +1912,7 @@ def test_datetime_select_defaults_to_time_zone_now_when_config_time_zone_is_set
 
     assert_dom_equal expected, datetime_select("post", "updated_at")
   ensure
-    Time.zone_default = nil
+    Time.zone = nil
   end
 
   def test_datetime_select_with_html_options_within_fields_for
diff --git a/activesupport/lib/active_support/core_ext/date/calculations.rb b/activesupport/lib/active_support/core_ext/date/calculations.rb
index f34185f22cbeb5df0119c2053566088cd424ef0b..724e076407d4b7a2c50e5952c72fdc80f508263d 100644
--- a/activesupport/lib/active_support/core_ext/date/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date/calculations.rb
@@ -36,9 +36,9 @@ def tomorrow
       ::Date.current.tomorrow
     end
 
-    # Returns Time.zone.today when config.time_zone is set, otherwise just returns Date.today.
+    # Returns Time.zone.today when <tt>Time.zone</tt> or <tt>config.time_zone</tt> are set, otherwise just returns Date.today.
     def current
-      ::Time.zone_default ? ::Time.zone.today : ::Date.today
+      ::Time.zone ? ::Time.zone.today : ::Date.today
     end
   end
 
diff --git a/activesupport/lib/active_support/core_ext/date/zones.rb b/activesupport/lib/active_support/core_ext/date/zones.rb
index 3a83af6be27e738e88c063dbd655f9f93d5931d0..a70b47b7bc8bcd650ea108405cfe502ab6ad1c8a 100644
--- a/activesupport/lib/active_support/core_ext/date/zones.rb
+++ b/activesupport/lib/active_support/core_ext/date/zones.rb
@@ -2,10 +2,10 @@
 require 'active_support/core_ext/time/zones'
 
 class Date
-  # Converts Date to a TimeWithZone in the current zone if Time.zone_default is set,
-  # otherwise converts Date to a Time via Date#to_time
+  # Converts Date to a TimeWithZone in the current zone if Time.zone or Time.zone_default
+  # is set, otherwise converts Date to a Time via Date#to_time
   def to_time_in_current_zone
-    if ::Time.zone_default
+    if ::Time.zone
       ::Time.zone.local(year, month, day)
     else
       to_time
diff --git a/activesupport/lib/active_support/core_ext/date_time/calculations.rb b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
index 1dc3933e128d1d64595b7714f8d61b57ca963f48..8d01376f1d8a68302ef0b0d9a7257134a9cf4335 100644
--- a/activesupport/lib/active_support/core_ext/date_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
@@ -9,8 +9,9 @@ def local_offset
       ::Time.local(2007).utc_offset.to_r / 86400
     end
 
+    # Returns <tt>Time.zone.now.to_datetime</tt> when <tt>Time.zone</tt> or <tt>config.time_zone</tt> are set, otherwise returns <tt>Time.now.to_datetime</tt>.
     def current
-      ::Time.zone_default ? ::Time.zone.now.to_datetime : ::Time.now.to_datetime
+      ::Time.zone ? ::Time.zone.now.to_datetime : ::Time.now.to_datetime
     end
   end
 
diff --git a/activesupport/lib/active_support/core_ext/time/calculations.rb b/activesupport/lib/active_support/core_ext/time/calculations.rb
index fa052fa86b9ff106766abb85b81fc5f46dea7d99..6e4b69f6816b11d7897da6a2cc076158712b3983 100644
--- a/activesupport/lib/active_support/core_ext/time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/time/calculations.rb
@@ -41,9 +41,9 @@ def local_time(*args)
       time_with_datetime_fallback(:local, *args)
     end
 
-    # Returns <tt>Time.zone.now</tt> when <tt>config.time_zone</tt> is set, otherwise just returns <tt>Time.now</tt>.
+    # Returns <tt>Time.zone.now</tt> when <tt>Time.zone</tt> or <tt>config.time_zone</tt> are set, otherwise just returns <tt>Time.now</tt>.
     def current
-      ::Time.zone_default ? ::Time.zone.now : ::Time.now
+      ::Time.zone ? ::Time.zone.now : ::Time.now
     end
   end
 
diff --git a/activesupport/test/core_ext/date_ext_test.rb b/activesupport/test/core_ext/date_ext_test.rb
index b4d7633e5f53838d8c6bf7b172509977969b50d1..03b84ae2e52656e3ac45bd5abe04a35284fa7c70 100644
--- a/activesupport/test/core_ext/date_ext_test.rb
+++ b/activesupport/test/core_ext/date_ext_test.rb
@@ -259,7 +259,7 @@ def test_yesterday_constructor
     assert_equal Date.current - 1, Date.yesterday
   end
 
-  def test_yesterday_constructor_when_zone_default_is_not_set
+  def test_yesterday_constructor_when_zone_is_not_set
     with_env_tz 'UTC' do
       with_tz_default do
         Time.stubs(:now).returns Time.local(2000, 1, 1)
@@ -268,7 +268,7 @@ def test_yesterday_constructor_when_zone_default_is_not_set
     end
   end
 
-  def test_yesterday_constructor_when_zone_default_is_set
+  def test_yesterday_constructor_when_zone_is_set
     with_env_tz 'UTC' do
       with_tz_default ActiveSupport::TimeZone['Eastern Time (US & Canada)'] do # UTC -5
         Time.stubs(:now).returns Time.local(2000, 1, 1)
@@ -281,7 +281,7 @@ def test_tomorrow_constructor
     assert_equal Date.current + 1, Date.tomorrow
   end
 
-  def test_tomorrow_constructor_when_zone_default_is_not_set
+  def test_tomorrow_constructor_when_zone_is_not_set
     with_env_tz 'UTC' do
       with_tz_default do
         Time.stubs(:now).returns Time.local(1999, 12, 31)
@@ -290,7 +290,7 @@ def test_tomorrow_constructor_when_zone_default_is_not_set
     end
   end
 
-  def test_tomorrow_constructor_when_zone_default_is_set
+  def test_tomorrow_constructor_when_zone_is_set
     with_env_tz 'UTC' do
       with_tz_default ActiveSupport::TimeZone['Europe/Paris'] do # UTC +1
         Time.stubs(:now).returns Time.local(1999, 12, 31, 23)
@@ -303,7 +303,7 @@ def test_since
     assert_equal Time.local(2005,2,21,0,0,45), Date.new(2005,2,21).since(45)
   end
 
-  def test_since_when_zone_default_is_set
+  def test_since_when_zone_is_set
     zone = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
     with_env_tz 'UTC' do
       with_tz_default zone do
@@ -317,7 +317,7 @@ def test_ago
     assert_equal Time.local(2005,2,20,23,59,15), Date.new(2005,2,21).ago(45)
   end
 
-  def test_ago_when_zone_default_is_set
+  def test_ago_when_zone_is_set
     zone = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
     with_env_tz 'UTC' do
       with_tz_default zone do
@@ -331,7 +331,7 @@ def test_beginning_of_day
     assert_equal Time.local(2005,2,21,0,0,0), Date.new(2005,2,21).beginning_of_day
   end
 
-  def test_beginning_of_day_when_zone_default_is_set
+  def test_beginning_of_day_when_zone_is_set
     zone = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
     with_env_tz 'UTC' do
       with_tz_default zone do
@@ -345,7 +345,7 @@ def test_end_of_day
     assert_equal Time.local(2005,2,21,23,59,59,999999.999), Date.new(2005,2,21).end_of_day
   end
 
-  def test_end_of_day_when_zone_default_is_set
+  def test_end_of_day_when_zone_is_set
     zone = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
     with_env_tz 'UTC' do
       with_tz_default zone do
@@ -367,7 +367,7 @@ def test_xmlschema
     end
   end
 
-  def test_xmlschema_when_zone_default_is_set
+  def test_xmlschema_when_zone_is_set
     with_env_tz 'UTC' do
       with_tz_default ActiveSupport::TimeZone['Eastern Time (US & Canada)'] do # UTC -5
         assert_match(/^1980-02-28T00:00:00-05:?00$/, Date.new(1980, 2, 28).xmlschema)
@@ -407,7 +407,7 @@ def test_future
     assert_equal true, Date.new(2000,1,2).future?
   end
 
-  def test_current_returns_date_today_when_zone_default_not_set
+  def test_current_returns_date_today_when_zone_not_set
     with_env_tz 'US/Central' do
       Time.stubs(:now).returns Time.local(1999, 12, 31, 23)
       assert_equal Date.new(1999, 12, 31), Date.today
@@ -415,15 +415,15 @@ def test_current_returns_date_today_when_zone_default_not_set
     end
   end
 
-  def test_current_returns_time_zone_today_when_zone_default_set
-    Time.zone_default = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
+  def test_current_returns_time_zone_today_when_zone_is_set
+    Time.zone = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
     with_env_tz 'US/Central' do
       Time.stubs(:now).returns Time.local(1999, 12, 31, 23)
       assert_equal Date.new(1999, 12, 31), Date.today
       assert_equal Date.new(2000, 1, 1), Date.current
     end
   ensure
-    Time.zone_default = nil
+    Time.zone = nil
   end
 
   def test_date_advance_should_not_change_passed_options_hash
@@ -441,11 +441,11 @@ def with_env_tz(new_tz = 'US/Eastern')
     end
 
     def with_tz_default(tz = nil)
-      old_tz = Time.zone_default
-      Time.zone_default = tz
+      old_tz = Time.zone
+      Time.zone = tz
       yield
     ensure
-      Time.zone_default = old_tz
+      Time.zone = old_tz
     end
 end
 
diff --git a/activesupport/test/core_ext/date_time_ext_test.rb b/activesupport/test/core_ext/date_time_ext_test.rb
index 8edb95b63a5cdb49933e54012342e39f4522bd57..456736cbad29a26e5734a384d1007a140e562e05 100644
--- a/activesupport/test/core_ext/date_time_ext_test.rb
+++ b/activesupport/test/core_ext/date_time_ext_test.rb
@@ -282,21 +282,21 @@ def test_future_without_offset
     assert_equal true,  DateTime.civil(2005,2,10,20,30,46).future?
   end
 
-  def test_current_returns_date_today_when_zone_default_not_set
+  def test_current_returns_date_today_when_zone_is_not_set
     with_env_tz 'US/Eastern' do
       Time.stubs(:now).returns Time.local(1999, 12, 31, 23, 59, 59)
       assert_equal DateTime.new(1999, 12, 31, 23, 59, 59, Rational(-18000, 86400)), DateTime.current
     end
   end
 
-  def test_current_returns_time_zone_today_when_zone_default_set
-    Time.zone_default = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
+  def test_current_returns_time_zone_today_when_zone_is_set
+    Time.zone = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
     with_env_tz 'US/Eastern' do
       Time.stubs(:now).returns Time.local(1999, 12, 31, 23, 59, 59)
       assert_equal DateTime.new(1999, 12, 31, 23, 59, 59, Rational(-18000, 86400)), DateTime.current
     end
   ensure
-    Time.zone_default = nil
+    Time.zone = nil
   end
 
   def test_current_without_time_zone
diff --git a/activesupport/test/core_ext/duration_test.rb b/activesupport/test/core_ext/duration_test.rb
index 6a01eeed6ba800b5153837d8f9b075fcb55160f5..c0b529d9f8ca8933f0c9aa01172740464185e832 100644
--- a/activesupport/test/core_ext/duration_test.rb
+++ b/activesupport/test/core_ext/duration_test.rb
@@ -89,8 +89,8 @@ def test_since_and_ago_with_fractional_weeks
     assert_in_delta((7 * 24 * 1.7).hours.ago(t), 1.7.weeks.ago(t), 1)
   end
 
-  def test_since_and_ago_anchored_to_time_now_when_time_zone_default_not_set
-    Time.zone_default = nil
+  def test_since_and_ago_anchored_to_time_now_when_time_zone_is_not_set
+    Time.zone = nil
     with_env_tz 'US/Eastern' do
       Time.stubs(:now).returns Time.local(2000)
       # since
@@ -102,8 +102,8 @@ def test_since_and_ago_anchored_to_time_now_when_time_zone_default_not_set
     end
   end
 
-  def test_since_and_ago_anchored_to_time_zone_now_when_time_zone_default_set
-    Time.zone_default = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
+  def test_since_and_ago_anchored_to_time_zone_now_when_time_zone_is_set
+    Time.zone = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
     with_env_tz 'US/Eastern' do
       Time.stubs(:now).returns Time.local(2000)
       # since
@@ -116,7 +116,7 @@ def test_since_and_ago_anchored_to_time_zone_now_when_time_zone_default_set
       assert_equal 'Eastern Time (US & Canada)', 5.seconds.ago.time_zone.name
     end
   ensure
-    Time.zone_default = nil
+    Time.zone = nil
   end
 
   def test_adding_hours_across_dst_boundary
diff --git a/activesupport/test/core_ext/numeric_ext_test.rb b/activesupport/test/core_ext/numeric_ext_test.rb
index 6ef4e37b2678e78406e77350043812c4418e858f..3a2452b4b058c2f62cd1d04aa93612272e54ef56 100644
--- a/activesupport/test/core_ext/numeric_ext_test.rb
+++ b/activesupport/test/core_ext/numeric_ext_test.rb
@@ -89,8 +89,8 @@ def test_add_one_year_to_leap_day
     assert_equal DateTime.civil(2005,2,28,15,15,10), DateTime.civil(2004,2,29,15,15,10) + 1.year
   end
 
-  def test_since_and_ago_anchored_to_time_now_when_time_zone_default_not_set
-    Time.zone_default = nil
+  def test_since_and_ago_anchored_to_time_now_when_time_zone_is_not_set
+    Time.zone = nil
     with_env_tz 'US/Eastern' do
       Time.stubs(:now).returns Time.local(2000)
       # since
@@ -102,8 +102,8 @@ def test_since_and_ago_anchored_to_time_now_when_time_zone_default_not_set
     end
   end
 
-  def test_since_and_ago_anchored_to_time_zone_now_when_time_zone_default_set
-    Time.zone_default = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
+  def test_since_and_ago_anchored_to_time_zone_now_when_time_zone_is_set
+    Time.zone = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
     with_env_tz 'US/Eastern' do
       Time.stubs(:now).returns Time.local(2000)
       # since
@@ -116,7 +116,7 @@ def test_since_and_ago_anchored_to_time_zone_now_when_time_zone_default_set
       assert_equal 'Eastern Time (US & Canada)', 5.ago.time_zone.name
     end
   ensure
-    Time.zone_default = nil
+    Time.zone = nil
   end
 
   protected
diff --git a/activesupport/test/core_ext/time_with_zone_test.rb b/activesupport/test/core_ext/time_with_zone_test.rb
index 5c226c2d09f29567caaa59e4fe379389a3e98d77..bafa335a09cdf344b5219a75cb0426287aa57e22 100644
--- a/activesupport/test/core_ext/time_with_zone_test.rb
+++ b/activesupport/test/core_ext/time_with_zone_test.rb
@@ -768,10 +768,10 @@ def test_in_time_zone_with_time_local_instance
   end
 
   def test_localtime
-    Time.zone_default = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
+    Time.zone = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
     assert_equal @dt.in_time_zone.localtime, @dt.in_time_zone.utc.to_time.getlocal
   ensure
-    Time.zone_default = nil
+    Time.zone = nil
   end
 
   def test_use_zone
@@ -801,7 +801,7 @@ def test_time_zone_getter_and_setter
     assert_equal nil, Time.zone
   end
 
-  def test_time_zone_getter_and_setter_with_zone_default
+  def test_time_zone_getter_and_setter_with_zone_default_set
     Time.zone_default = ActiveSupport::TimeZone['Alaska']
     assert_equal ActiveSupport::TimeZone['Alaska'], Time.zone
     Time.zone = ActiveSupport::TimeZone['Hawaii']
@@ -809,6 +809,7 @@ def test_time_zone_getter_and_setter_with_zone_default
     Time.zone = nil
     assert_equal ActiveSupport::TimeZone['Alaska'], Time.zone
   ensure
+    Time.zone = nil
     Time.zone_default = nil
   end
 
@@ -849,7 +850,7 @@ def test_time_zone_setter_with_invalid_zone
     assert_nil Time.zone
   end
 
-  def test_current_returns_time_now_when_zone_default_not_set
+  def test_current_returns_time_now_when_zone_not_set
     with_env_tz 'US/Eastern' do
       Time.stubs(:now).returns Time.local(2000)
       assert_equal false, Time.current.is_a?(ActiveSupport::TimeWithZone)
@@ -857,8 +858,8 @@ def test_current_returns_time_now_when_zone_default_not_set
     end
   end
 
-  def test_current_returns_time_zone_now_when_zone_default_set
-    Time.zone_default = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
+  def test_current_returns_time_zone_now_when_zone_set
+    Time.zone = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
     with_env_tz 'US/Eastern' do
       Time.stubs(:now).returns Time.local(2000)
       assert_equal true, Time.current.is_a?(ActiveSupport::TimeWithZone)
@@ -866,7 +867,7 @@ def test_current_returns_time_zone_now_when_zone_default_set
       assert_equal Time.utc(2000), Time.current.time
     end
   ensure
-    Time.zone_default = nil
+    Time.zone = nil
   end
 
   protected