As you may know, as of April 21 2015 Google will rank mobile-friendly websites higher than those that are not mobile-friendly. If you’re not sure whether you pass the mobile-friendly test, Google provides a link where you can simply enter your site URL, and see some general results. If not mobile-friendly, Google offers some advice but often these pieces of advice can’t be directly applied to a WordPress site, although it does go some way to explain general design principals of making a WordPress site more mobile-friendly.
Read more Making your WordPress site mobile friendly for Google