WordPress has a wonderful feature allowing you to schedule posts to publish at a future date. This is perfect for when you'll be on vacation or you need a post to go online at an exact time while you're away from your computer.
Unfortunately, this feature within WordPress can sometimes be inconsistent. While some users have never experienced an issue with this, others have consistently missed scheduled post times.
"There's a Plugin for That"
If you experience this issue, there is a plugin that can assist by routinely checking for any missed scheduled posts. It's called Scheduled Post Trigger and will check your database for any missed posts each time a visitor loads your blog (not on admin visits.)
Install Scheduled Post Trigger
Login to your Wordpress admin and go to Plugins > Add New
Search the plugins database for Scheduled Post Trigger
Click to Install the plugin. Then to Activate it.
That's all! It will start working in the background.
Hopefully in the future the WordPress Core developer teams will be able to find a solution that resolves this issue for all users. Until that comes it's nice to know that there are options like the plugin above.