Traditional wisdom suggests Tuesday through Thursday mornings. But the long answer is much more complicated, and like most e-mail marketing questions, depends on numerous variables and your specific situation. Before we get to the longer answer, below are a couple of fairly straightforward strategies to determine the best time to send out promotional messages:

• Survey your subscribers via e-mail as to what time of the day they would most like to receive e-mails, and give them a half dozen time periods to choose from. Then send e-mails to the responding subscribers based on their preferences.
• If you have an opt-in form on your Web site, allow the subscribers to select the time period they’d like to receive e-mails when they sign-up. If you notice a trend you might think about changing the launch day and time of your e-Newsletter.
• Conduct a mini-focus group by contacting a dozen of your best subscribers (meaning a high open and click-through rate) and find out what time they’d like to receive your messages. Of course these conversations can serve a dual role to help you learn what types of information and format would be most valuable and preferred.
• Test. The best method is always to conduct tests. Segment your list into equal random groups and e-mail the identical message to each segment at key time periods (keeping in mind differences by time zone).
• Consider segmenting based on time zone. Segment your list according to their state/zip code and corresponding time zones. When you’ve determined optimum mailing times this ensures that your message reaches subscribers across the country all at the same local time period.

Now to the more complex answer. For the past several years almost every industry report has shown that the best time to e-mail business-to-business messages is Tuesday through Thursday mornings. And because of this, many e-mail marketers have flocked to these days en mass.

Now more “progressive” e-mail marketing experts are suggesting mailing on either Monday or Friday. The logic is that because the vast majority of firms are mailing in the same time frame, your message has a greater chance to be lost among dozens of other messages. One example they use is a traditional, or “snail” mail direct mailer. If you were to conduct a paper-based direct mail campaign would you prefer that, when your prospects go to their mailboxes, your mailer was the only one, or just one of ten sent on a more “popular” day?

But again, as outlined above, testing and speaking directly with your clients and prospects will produce the best chance for success. I would like to be able to say, “this is the perfect day for you to send out your e-Newsletter,” but with all the variables that just isn’t possible.