diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 21c79949cad24655722816a2ea1c4c8dfb47d999..a383a05941a482051142b8613bf38879e425ab87 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,8 @@
+*   Fix parsing JSON time in `YYYY-MM-DD hh:mm:ss` (without `Z`).
+    Before such time was considered in UTC timezone, now, to comply with standard, it uses local timezone.
+
+    *Grzegorz Witek*
+
 *   Match `HashWithIndifferentAccess#default`'s behaviour with `Hash#default`.
 
     *David Cornu*
diff --git a/activesupport/lib/active_support/json/decoding.rb b/activesupport/lib/active_support/json/decoding.rb
index 2932954f03c73ef251ece161a5351158a6e31e1a..64e4b0e7a9b479868fbb8b2936470db52d00c318 100644
--- a/activesupport/lib/active_support/json/decoding.rb
+++ b/activesupport/lib/active_support/json/decoding.rb
@@ -8,7 +8,8 @@ module ActiveSupport
 
   module JSON
     # matches YAML-formatted dates
-    DATE_REGEX = /^(?:\d{4}-\d{2}-\d{2}|\d{4}-\d{1,2}-\d{1,2}[T \t]+\d{1,2}:\d{2}:\d{2}(\.[0-9]*)?(([ \t]*)Z|[-+]\d{2}?(:\d{2})?))$/
+    DATE_REGEX = /^\d{4}-\d{2}-\d{2}$/
+    DATETIME_REGEX = /^(?:\d{4}-\d{2}-\d{2}|\d{4}-\d{1,2}-\d{1,2}[T \t]+\d{1,2}:\d{2}:\d{2}(\.[0-9]*)?(([ \t]*)Z|[-+]\d{2}?(:\d{2})?)?)$/
 
     class << self
       # Parses a JSON string (JavaScript Object Notation) into a hash.
@@ -48,7 +49,13 @@ def convert_dates_from(data)
           nil
         when DATE_REGEX
           begin
-            DateTime.parse(data)
+            Date.parse(data)
+          rescue ArgumentError
+            data
+          end
+        when DATETIME_REGEX
+          begin
+            Time.zone.parse(data)
           rescue ArgumentError
             data
           end
diff --git a/activesupport/test/json/decoding_test.rb b/activesupport/test/json/decoding_test.rb
index f2fc456f4b9e16129a4cd0c0502f2050464907fb..887ef1681df7d9630b12894ccfefcb7f22b900b3 100644
--- a/activesupport/test/json/decoding_test.rb
+++ b/activesupport/test/json/decoding_test.rb
@@ -1,8 +1,11 @@
 require 'abstract_unit'
 require 'active_support/json'
 require 'active_support/time'
+require 'time_zone_test_helpers'
 
 class TestJSONDecoding < ActiveSupport::TestCase
+  include TimeZoneTestHelpers
+
   class Foo
     def self.json_create(object)
       "Foo"
@@ -24,10 +27,11 @@ def self.json_create(object)
     %(["2007-01-01 01:12:34 Z"])                 => [Time.utc(2007, 1, 1, 1, 12, 34)],
     %(["2007-01-01 01:12:34 Z", "2007-01-01 01:12:35 Z"]) => [Time.utc(2007, 1, 1, 1, 12, 34), Time.utc(2007, 1, 1, 1, 12, 35)],
     # no time zone
-    %({"a": "2007-01-01 01:12:34"})              => {'a' => "2007-01-01 01:12:34"},
+    %({"a": "2007-01-01 01:12:34"})              => {'a' => Time.new(2007, 1, 1, 1, 12, 34, "-05:00")},
     # invalid date
     %({"a": "1089-10-40"})                       => {'a' => "1089-10-40"},
     # xmlschema date notation
+    %({"a": "2009-08-10T19:01:02"})              => {'a' => Time.new(2009, 8, 10, 19, 1, 2, "-04:00")},
     %({"a": "2009-08-10T19:01:02Z"})             => {'a' => Time.utc(2009, 8, 10, 19, 1, 2)},
     %({"a": "2009-08-10T19:01:02+02:00"})        => {'a' => Time.utc(2009, 8, 10, 17, 1, 2)},
     %({"a": "2009-08-10T19:01:02-05:00"})        => {'a' => Time.utc(2009, 8, 11, 00, 1, 2)},
@@ -72,10 +76,12 @@ def self.json_create(object)
 
   TESTS.each_with_index do |(json, expected), index|
     test "json decodes #{index}" do
-      with_parse_json_times(true) do
-        silence_warnings do
-          assert_equal expected, ActiveSupport::JSON.decode(json), "JSON decoding \
-          failed for #{json}"
+      with_tz_default 'Eastern Time (US & Canada)' do
+        with_parse_json_times(true) do
+          silence_warnings do
+            assert_equal expected, ActiveSupport::JSON.decode(json), "JSON decoding \
+            failed for #{json}"
+          end
         end
       end
     end