There are more than 71 million WordPress sites on the internet and new sites are going live every single day.

One of the best ways to get up and running quickly — especially if you don't have much design or development experience — is to use a theme. And some of the very best themes out there are completely free!

Every month we'll be bringing you our pick of the best free WordPress themes released in the previous four weeks. Here are our favorites for October:

Hostmarks

This minimalistic theme has two options — blog and full page style — that work great for creating a blog. With optional widgets for tagging, an image gallery, video and more, this theme has almost every tool a blogger needs to get started. The theme is responsive and colors can be customized.

Luminescence Lite

Luminescence Lite has a super-modern and attractive look built in a responsive format. The blog theme is built in an easy-to read classic style with modern type and detailing. The theme contains social sharing widgets and other fun extras such as custom gallery styling and multiple post formats. The responsive theme is Bootstrap-based and includes a child theme. For a free theme, Luminescence Lite has a package of features that is hard to top.

Adelle

With a soft pink color scheme and light look, Adelle is a feminine-styled theme designed for bloggers. The responsive theme includes customizable menus and works in a variety of browsers. The theme also features a sidebar with multiple widgets for blog categories, an archive and Twitter and Facebook feeds.

Cherry Blossom

Cherry Blossom is a simple blog theme designed in a feminine style. The featured color is pink and headers use script typefaces. The theme is responsive and includes a style for forms and tables.

Custom

If search engine optimization is not one of your strengths, Custom might be a good theme option. The SEO-friendly, responsive theme has a lot of little add-ins to make optimizing your site for search engines easier. The simple theme is packed with options for tagging and custom color, header, menu and background options.

Kotenhanagara

A fun, Japanese styled theme that is easy to use. The flower background in black and white pairs with a color-blocked style (you can pick the color) and simple blog and sidebar format.

Lobster

This theme is named after one a quite popular font of the same name — Lobster. The Bootstrap-based theme is built with mobile in mind and works nicely as a simple mobile site outline. The color palette is customizable and the theme comes with Font Awesome (which includes more than 350 icons) and Google Fonts support.

Church

Despite its name, Church is a responsive theme that can work for a variety of different websites, from business to personal to blogging. The theme allows for customization of colors, footers, menus and header. Church also has a nice area for widgets that is somewhat oversized.

Dusky

Dusky is built with a beautiful, dark color palette as the name implies and is a great framework for a portfolio or image-heavy website. The theme is fully responsive and supports images as well as video. Menus are customizable and photos feature optional text excerpts.

Openstrap

This free theme comes with a lot of extras that you might not expect – 11 widget options, three menu location options, six layouts and two front page templates. Openstrap, which is Bootstrap based, is also fully responsive and offers a variety of other customization options. The design is simple with a modern, flat style and is optimized for search as well.

Sixteen

This photo-heavy blog theme uses a grid layout and includes parallax effects. The theme is responsive and offers a variety of customization options, it's perfect for a site that features great images and includes galleries and is retina ready.

Accessible Zen

Accessible Zen is a minimalistic theme built on a responsive platform. The theme works well for a simple blog because of its one-column format and clean typography. It comes with nine different post-style options. The theme is also made to showcase the blogger's Gravatar in the header. But can be customized with another image.

Point

Point is another free theme packed with many of the extras that are frequently found in premium themes. It is responsive and has multiple layouts, backgrounds and color palettes. The theme is SEO optimized, making it easy for you to go online in a hurry, and includes a custom widget library, including a very nice related posts widget for bloggers.

Shprink One

This theme with the funny name is super-customizable, with options for slideshows, different front pages, layout and theme customization, multiple language support, and custom menus and widgets. For a free theme, you get a lot of options to choose from; plus, Shprink One includes fun features such as infinite scrolling. The Bootstrap-based theme is fully responsive.

Epic

This super-simple blog theme does not have many bells and whistles but would make a great simple journal. It is responsive and includes buttons for social sharing.

Simpleo

The fully responsive Simpleo theme is a great option for a businesses launching a website with WordPress because it comes with integrated e-commerce tools and functionality. The theme offers a variety of customization options so that your site has a look of its own and supports social media integration, blogging and is retina display ready.

Traffica

Traffica is a simple theme that is optimized for search and includes a lot of customization options from color to log usage to font selection. The responsive theme includes six widget locations, allows for featured images and includes an optional sidebar.

Espressionista

With a static header and multi-column grid, Espressionista is an easy-to-look-at theme. With quite a few customization options — you can change the color or type palette — anyone can publish an attractive site. The color outline used is somewhat flat by design and is responsive, giving this theme a modern look and feel.

Fancier

If you love the look of Pinterest, Fancier is a theme after your own heart. The theme uses a four-column card-style grid to group blog entries. While the theme has a nice look and feel, it is not responsive and you do need strong images to make the most of this theme.

Tribbiani

This high-color, high-contrast theme has an uber-modern look and feel. Tribbiani is a good option for image heavy site design; it is not the best option for sites that lack images. One of the key features of the theme is the giant image slider as part of the retina-ready template. Tribbiani is also has embedded SEO tools, supports galleries and commenting, and has several neat CSS transition effects available. The theme also integrates social media sharing and has some customization options.

Gray – Base Plate

The gray and orange Base Plate theme has something of a futuristic look and feel. The theme is responsive and has options for a widescreen display, plus smaller boxes below, making it a flexible for different applications. While this theme does not feature a lot of extras, it is a good base template.

Green Eye

Green Eye is a feature-filled free theme. The responsive theme is marketed toward environmentally friendly businesses or websites, but has a lot of practical use. The theme has a professional look and lots of customization options from background images to banners to widgets. The theme also features lightweight code and is a great starter theme that can be used to showcase or link to other pages.

Mixfolio

With a responsive grid layout, Mixfolio is a great option for a portfolio or blog. One of the best features of this theme is the ability to select a post format — image, gallery, video, standard, quote or link — and the design matches corresponds to the format. And it’s all customizable, without having to code.

Have we missed a free WordPress theme that should have been included? What features are essential in a free WordPress theme? Let us know in the comments.