A handy tool to use is the scheduling tool. I use it quite often (like today).
On your WordPress site while you’re creating your blog post you should find something that says status.

After you click status a drop down option will appear.

It’ll ask you if you’d like to publish immediately and the privacy setting of the post. If you click publish immediately it’ll let you pick a day to choose from.

Just click a date and it’ll say schedule instead of post. This is really handy for days you know you’ll be gone so you can write in advance to keep the streak going.