The most obvious, simplest and platform-independent way to achieve your request is to format the blog title entries as:
YYYY-MM-DD : title
Another alternative is to alter the publication date. This works very well if all your blog entries are about events in the past. I have used this approach for a news blog, in which stories about news in the media were published with their original publication date.
There are several wordpress plugins. For instance, this one seems to do the job by placing blog entries on a vertical scroll. It is likely that you may need to still follow the suggestion of altering the publication date in order to place things in the correct order.
Finally, if you are using wordpress and feel adventurous enough to try and tweak it yourself, there is a field called "meta" where you can store additional information, and, more importantly, you can retrieve it by modifying the PHP code of your template. You could store a date, retrieve it and display between the title and the main text of the blog post, for instance accompanied by a horizontal progress bar.