People's routines drive these stats, which I found extremely interesting.
When are people really focused on email?
Mornings between 8am and 9am for opens and click-throughs. This is when people are just getting into work and settling in for their day.
Afternoons 3pm to 8pm for opens & 3pm to 4pm for click-throughs. This is the after lunch time, when people are getting back into their afternoon routine.
Almost 40% of all messages are sent between 6am and noon, creating inbox clutter. This is where your message can get lost.
23.63% of all email opens occur within the first hour after delivery. The results drop by half within the second hour after delivery. Within the 3rd hour, they drop another 30%. 5 hours after delivery, the results drop more than 90%.
So you want to send your email to arrive at the recipients desk no later than 1 hour before top open times. Which are morning 8am to 9am and early afternoon 3pm to 4pm.
Most emails are in your inbox in the morning, so the ones that get sent in the afternoon have more of a chance at being noticed, opened and clicked.
Now, what day of the week for best effectiveness? Only Monday to Wednesday. Thursday and Friday are no go. You will not get the most out of your campaign.
5:00 pm, most people are on their way home
6:00 pm, most people are eating
7:00 pm, most people are bathing children
8:00 pm, people to start reading email again
So, don't send an email on Friday at 5pm. No one will hear it :)