Every post that you publish on your Tumblr blog has a date associated with it -- it's then down to the theme you have installed to determine how this date is displayed and in what format. If you're not happy with the way blog post dates are displayed on your Tumblr, or if you can't see them at all, you can edit your theme's HTML directly via the Customize screen.

Step 1

Log in to Tumblr, and then click the "Customize" link. The blog customization screen appears, and may include integrated options for displaying dates, depending on the theme -- check the list of options on the left.

Step 2

Click "Edit HTML" to make direct changes to the theme code. Scroll down to find the section showing the structure of each post type, often preceded with a "{block:Date}" label.

Step 3

Enter the labels "{Month}", "{DayOfMonth}" and "{Year}" (without the quotes) anywhere in the code to display the date in the format "January 1 2014." There are several date variables to choose from; a full list is available in the Tumblr custom HTML documentation (see link in Resources).

Step 4

Click "Update Preview" to see how your changes look on your blog. If you're happy, select "Save" to confirm the modifications.