Rainlendar is described as 'Feature rich calendar application that is easy to use and doesn't take much space on your desktop. The application is platform independent so you can run it on all major operating systems: Windows, Linux and Mac OS X' and is a very popular Calendar app in the office & productivity category. There are more than 50 alternatives to Rainlendar for a variety of platforms, including Windows, Web-based, iPhone, Mac and Android apps. The best Rainlendar alternative is Google Calendar. It's not free, so if you're looking for a free alternative, you could try Google Calendar or Fossify Calendar. Other great apps like Rainlendar are Tuta Calendar, Etar, Fantastical and Notion Calendar.