Skim Alternatives for Windows
Skim is not available for Windows but there are plenty of alternatives that runs on Windows with similar functionality. The most popular Windows alternative is 
SumatraPDF, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 50 alternatives to Skim and many of them are available for Windows so hopefully you can find a suitable replacement. Other interesting Windows alternatives to Skim are 
Foxit Reader (Free Personal), 
Okular (Free, Open Source), 
PDF-XChange Editor (Freemium) and 
Adobe Acrobat Reader DC (Freemium).
- Sumatra PDF is a slim, free, open-source PDF/DjVu/EPUB/XPS/CHM/CBR/CBZ/MOBI/FB2 viewer for Windows.Why another PDF reader? View 87 alternatives to SumatraPDF
- Free • Open Source
- Windows
- PortableApps.com
SumatraPDF vs Skim
no notes extraction available - Free PDF software that enables you to create, annotate, share, and collaborate on PDF documents. View 96 alternatives to Foxit Reader
Bundleware
The installer tries to install McAfee WebAdvisor and PhantomPDF Business. These can be skipped by clicking Decline on each.
- Free Personal • Proprietary
- Mac
- Windows
- Linux
- Android
- iPhone
- Windows S
- Android Tablet
- Windows Phone
- iPad
- ReactOS
- Okular is a universal document viewer developed by KDE. Okular works on multiple platforms, including but not limited to Linux, Windows, macOS, *BSD, etc. View 87 alternatives to Okular
- The smallest, fastest, most feature-rich PDF editor/viewer available * Full Direct Content Editing (text based PDFs, not scanned/image based PDFs) * Includes OCR feature... View 102 alternatives to PDF-XChange Editor
- Freemium • Proprietary
- Windows
- Wine
- Adobe Acrobat Reader DC is a powerful software for viewing, printing, and annotating PDFs. View 84 alternatives to Adobe Acrobat Reader DC
- Freemium • Proprietary
- Mac
- Windows
- Android
- iPhone
- Chrome OS
- Windows Phone
- iPad
- Blackberry 10
- Xournal++ is a hand note taking software written in C++ with the target of flexibility, functionality and speed. View 18 alternatives to Xournal++
- Free • Open Source
- Mac
- Windows
- Linux
- Online
- Android
- Chrome OS
- Android Tablet
- Self-Hosted
Xournal++ vs Skim
violoncello Xournal++ allows for annotating pdfs with an active pen - MuPDF is a highly versatile, customizable PDF and XPS interpreter solution that can be used across a wide range of applications as a PDF renderer, viewer, or toolkit. View 64 alternatives to MuPDF
- Master PDF Editor is complete solution for editing PDF and XPS files. You can insert, edit, remove, copy, add images or graphics. Export, import, remove and change page layouts. View 107 alternatives to Master PDF Editor
- Freemium • Proprietary
- Mac
- Windows
- Linux
- Nitro Pro gives you everything you need to create, convert, edit, sign, and share 100% industry-standard PDF files. View 141 alternatives to Nitro Pro
- Xournal is an application for notetaking, sketching, keeping a journal using a stylus. View 41 alternatives to xournal
Discontinued
It hasn't been updated since 2017, but there is an active fork Xournal++
- Free • Open Source
- Windows
- Linux