diff --git a/.gitignore b/.gitignore
index 11e1cde..b9fe64f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@ pkg
 *.swp
 Gemfile.lock
 .bundle
+vendor/bundle
diff --git a/Gemfile b/Gemfile
index 3356734..a456694 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,4 +1,4 @@
-source 'http://rubygems.org'
+source 'https://rubygems.org'
 
 gem 'timetrap'
 gem 'timetrap-harvest'
diff --git a/formatters/day.rb b/formatters/day.rb
index 30908ce..c3da385 100644
--- a/formatters/day.rb
+++ b/formatters/day.rb
@@ -15,8 +15,12 @@ def output
     output = ''
     todays_duration = 0.0
     todays_entries = []
+    
+    # Determine the target date from entries or use today
+    target_date = determine_target_date
+    
     @entries.each do |entry|
-      if is_today(entry[:start], entry.end_or_now) && !@skip.include?(entry.sheet)
+      if is_target_date(entry[:start], entry.end_or_now, target_date) && !@skip.include?(entry.sheet)
         todays_duration += entry.duration
         todays_entries << entry
       end
@@ -28,10 +32,22 @@ def output
     return output
   end
 
-  def is_today(start_time, end_time)
-    return (Date.parse(start_time.strftime(DATE_FORMAT))..Date.parse(end_time.strftime(DATE_FORMAT))) === Date.today
+  def determine_target_date
+    # If entries exist, use the date of the last entry, otherwise use today
+    # This allows the formatter to work with filtered date ranges
+    if @entries.empty?
+      Date.today
+    else
+      # Use the latest date among the entries
+      @entries.map { |e| Date.parse(e[:start].strftime(DATE_FORMAT)) }.max || Date.today
+    end
+  end
+  private :determine_target_date
+
+  def is_target_date(start_time, end_time, target_date)
+    return (Date.parse(start_time.strftime(DATE_FORMAT))..Date.parse(end_time.strftime(DATE_FORMAT))) === target_date
   end
-  private :is_today
+  private :is_target_date
 
   def hours_to_seconds(hour_amount)
     return (hour_amount * 60.0 * 60.0)
diff --git a/spec/timetrap_formatters_spec.rb b/spec/timetrap_formatters_spec.rb
index c5b3bec..e43c346 100644
--- a/spec/timetrap_formatters_spec.rb
+++ b/spec/timetrap_formatters_spec.rb
@@ -1,4 +1,12 @@
 TEST_MODE = true # This tells timetrap not to use the real database.
+
+# Monkey patch for Ruby 3.2 compatibility with old RSpec version
+class File
+  class << self
+    alias_method :exists?, :exist? unless method_defined?(:exists?)
+  end
+end
+
 require 'rubygems'
 require 'bundler'
 Bundler.require
@@ -104,4 +112,45 @@ def invoke command
 OUTPUT
     end
   end
+
+  describe "day" do
+    before do
+      # Configure the day formatter settings
+      Timetrap::Config.stub(:[]).with('day_length_hours').and_return(8.0)
+      Timetrap::Config.stub(:[]).with('progress_width').and_return(40.0)
+      Timetrap::Config.stub(:[]).with('day_exclude_sheets').and_return([])
+      Timetrap::Config.stub(:[]).with('day_countdown').and_return(false)
+      Timetrap::Config.stub(:[]).with('formatter_search_paths').and_return(
+        [File.expand_path(File.join(File.dirname(__FILE__), '..', 'formatters'))]
+      )
+      
+      # Create entries for a past date (2013-07-29)
+      Timetrap::Entry.create( :sheet => 'work',
+        :note => 'past entry', :start => '2013-07-29 10:00:00', :end => '2013-07-29 14:00:00'
+      )
+    end
+
+    it "should correctly display entries for past dates" do
+      Timetrap::Timer.current_sheet = 'work'
+      invoke 'display --start "2013-07-29" --end "2013-07-29" --format day'
+      # Should show 4 hours of 8 hours = 50%
+      output = $stdout.string
+      output.should include('50%')
+      output.should include('4:00:00')
+    end
+
+    it "should correctly display entries for a different date" do
+      # Create entries for a specific date (not necessarily today)
+      Timetrap::Entry.create( :sheet => 'work',
+        :note => 'entry for specific date', :start => '2013-07-30 09:00:00', :end => '2013-07-30 11:00:00'
+      )
+      
+      Timetrap::Timer.current_sheet = 'work'
+      invoke "display --start \"2013-07-30\" --format day"
+      # Should show 2 hours of 8 hours = 25%
+      output = $stdout.string
+      output.should include('25%')
+      output.should include('2:00:00')
+    end
+  end
 end