Handle offset relative to TZ in options list (#39334)

app/helpers/settings_helper.rb

@@ -57,6 +57,10 @@ module SettingsHelper
     end
   end
 
+  def time_zone_options
+    ActiveSupport::TimeZone.all.map { |tz| ["(GMT#{tz.now.formatted_offset}) #{tz.name}", tz.tzinfo.name] }
+  end
+
   private
 
   def links_for_featured_tags(tags)

app/views/settings/preferences/appearance/show.html.haml

@@ -16,7 +16,7 @@
                 wrapper: :with_label
     .fields-group.fields-row__column.fields-row__column-6
       = f.input :time_zone,
-                collection: ActiveSupport::TimeZone.all.map { |tz| ["(GMT#{tz.formatted_offset}) #{tz.name}", tz.tzinfo.name] },
+                collection: time_zone_options,
                 hint: false,
                 selected: current_user.time_zone || Time.zone.tzinfo.name,
                 wrapper: :with_label

spec/helpers/settings_helper_spec.rb

@@ -50,4 +50,20 @@ RSpec.describe SettingsHelper do
       end
     end
   end
+
+  describe '#time_zone_options' do
+    subject { helper.time_zone_options }
+
+    context 'when summer time is in effect' do
+      before { travel_to(Date.new(2026, 6, 1)) }
+
+      it { is_expected.to include(['(GMT-08:00) Alaska', 'America/Juneau']) }
+    end
+
+    context 'when summer time is not in effect' do
+      before { travel_to(Date.new(2025, 12, 1)) }
+
+      it { is_expected.to include(['(GMT-09:00) Alaska', 'America/Juneau']) }
+    end
+  end
 end