diff --git a/ext/psych/lib/psych/scalar_scanner.rb b/ext/psych/lib/psych/scalar_scanner.rb
index dc6f9944fa..e1e59d37e3 100644
--- a/ext/psych/lib/psych/scalar_scanner.rb
+++ b/ext/psych/lib/psych/scalar_scanner.rb
@@ -91,7 +91,14 @@ module Psych
       return Time.at(time.to_i, us) unless md[3]
 
       tz = md[3].split(':').map { |digit| Integer(digit, 10) }
-      offset = tz.first * 3600 + ((tz[1] || 0) * 60)
+      offset = tz.first * 3600
+
+      if offset < 0
+        offset -= ((tz[1] || 0) * 60)
+      else
+        offset += ((tz[1] || 0) * 60)
+      end
+
       Time.at((time - offset).to_i, us)
     end
   end
diff --git a/ext/psych/lib/psych/visitors/yaml_tree.rb b/ext/psych/lib/psych/visitors/yaml_tree.rb
index 4df7b4d5db..5f757e9e1b 100644
--- a/ext/psych/lib/psych/visitors/yaml_tree.rb
+++ b/ext/psych/lib/psych/visitors/yaml_tree.rb
@@ -269,12 +269,12 @@ module Psych
 
       private
       def format_time time
-        formatted = time.strftime("%Y-%m-%d %H:%M:%S")
+        formatted = time.strftime("%Y-%m-%d %H:%M:%S.%9N")
         if time.utc?
-          formatted += ".%09dZ" % [time.nsec]
+          formatted += "Z"
         else
-          formatted += ".%09d %+.2d:%.2d" % [time.nsec,
-            time.gmt_offset / 3600, time.gmt_offset % 3600 / 60]
+          zone = time.strftime('%z')
+          formatted += " #{zone[0,3]}:#{zone[3,5]}"
         end
         formatted
       end
diff --git a/test/psych/visitors/test_to_ruby.rb b/test/psych/visitors/test_to_ruby.rb
index 077b8796a5..b5b8e1443d 100644
--- a/test/psych/visitors/test_to_ruby.rb
+++ b/test/psych/visitors/test_to_ruby.rb
@@ -112,10 +112,10 @@ description:
 
       def test_time
         now = Time.now
-        formatted = now.strftime("%Y-%m-%d %H:%M:%S") +
-          ".%09d %+.2d:%2d" % [ now.nsec,
-                                now.gmt_offset / 3600,
-                                now.gmt_offset % 3600 / 60]
+        zone = now.strftime('%z')
+        zone = " #{zone[0,3]}:#{zone[3,5]}"
+
+        formatted = now.strftime("%Y-%m-%d %H:%M:%S.%9N") + zone
 
         assert_equal now, Nodes::Scalar.new(formatted).to_ruby
       end