When I tell clients that they should try and post blogs on the same day / same time each week or month they panic that they might be busy on that day or such like. This is not the case, on most websites / blog sites you can put posts in ‘draft’ or even schedule them for a later date.
I am often asked by people if there is a best day to post blogs and as far as I am aware there is not, this is because not many websites are cached by Google every minute of every day (apart from sites like the BBC that are updated with fresh content every second!), on average (to my understanding), most websites are cached by Google every week or so.
However, if you post on the same day each week, at the same time Google will notice this and your rankings (and subsequent traffic) will begin to improve because of this.
I have a client I worked as a blog writer for; I recommended he posted blogs on the same day / same time. He started doing this every Friday at 12noon and his traffic more than doubled in three weeks so I know it works!
So when should you post blog posts – whenever you want but make sure it’s on the same day at the same time.