The typical consultant answer is 'test it' but there are some good places to start.

People generally start checking email when they show up to work (yes that includes personal). Sending around 8:30AM will give you a good shot of being at the top of their inbox then.

Another good time is before lunch break. Shoot for something around 12:00PM for this.

If you have an email provider that allows you to adapt your send to the local time, use that. But if not, go for EST. Close to 50% of the US population lives in that, with another 30% one hour behind in central.

When it comes to lead nurturing, the importance of getting the timing right is not necessarily about which day of the week and what time of day you send the emails. It's about how quickly you follow up with your new leads in the first place.

Check out this stat from HBR:
"Firms that tried to contact potential customers within an hour of receiving a query were nearly seven times as likely to qualify the lead (which we defined as having a meaningful conversation with a key decision maker) as those that tried to contact the customer even an hour later—and more than 60 times as likely as companies that waited 24 hours or longer."
Article here: https://hbr.org/2011/03/the-short-life-of-online-sales-leads/ar/1

In other words, that first email in your nurturing campaign should be sent nearly immediately, or at least within an hour of the conversion, when you're still top-of-mind for them. If you have a sales team, you should also set up an automatically-triggered email notification to the appropriate sales rep that a new lead has converted and should be contacted ASAP. (Every sales rep I've worked with has been THRILLED to receive these notifications.)

Lastly, if you are looking to get a sense for what days/times work best for email engagement, and your list is sizable enough, you might consider doing a 4-way split test, sending the same email content to each quarter of your list across 2 different days and 2 different times each day. This will give you even more data to work with than your typical 50/50 A/B test.

Let me know if you'd like to continue discussing strategy around setting up your nurturing campaigns. Happy to help!

It depends on your target market (who is your audience), what country they are in, target demographic (older/younger, male/female, what state of mind are they in relation to your offer), product being sold and how the conversion funnel turns the user into a buyer (pure online conversion, phone-assisted?), how long does the sales funnel take on average to convert the user, etc.

With the answer to those questions we can sketch out the ideal time/day to send the drip campaign and then validate by testing

Drip campaigns, as mentioned above, are automated sets of emails that go out based on specific timelines or user actions. They enable you to stay in touch with groups of people based on events like when a user signs up for an account or how often that user visits your site. Put simply, drip marketing is all about giving people the right information at the right time.
The beauty of drip emails is that this all happens automatically based on triggers and user segments that you define. Perhaps that is not so surprising, since they also found that people who read your drip emails are far more likely to click the links in them, with a 119% increase in click rate from drip emails. You can have specific drip campaigns for educating users, rewarding your best customers, helping people who hit a certain page on your site, and more. Most importantly, though, is that you can pin-point user groups with drip emails, segmenting your email list, and reaching the right people when they are ready to buy.
So, When Should You Use a Drip Campaign?
1. Nurturing Leads
Zapier sends new users a nurturing drip email to help them brainstorm automation ideas. Lead Nurturing can take many forms, like educating users on your service, helping them use certain features, or offering them free trials. You can't personally handhold every user through discovering and purchasing your product, but drip emails can do that work for you.

2. Welcoming
Meditation app Headspace welcomes new users with a playful drip email and a brief explanation about what they offer. You have done a great job at marketing and have attracted a ton of new people to sign up for a trial or request info about your products. Experian's white paper on welcome emails shows that these autoresponders enjoy a 58.7% open rate on average, while normal emails sit around 14.6%. So, craft a great welcome drip campaign, and you'll get the amazing engagement welcome emails receive and then keep the momentum going with follow-up messages.

3. Onboarding
Cloud storage app Box employs drip campaigns to teach people how to use their product. Pageviews and trial users are nice, but eventually you need your users to sign up or purchase something from you. By using automated emails, you can setup a system that helps to drive customers toward activation in your product. What you really want to do here is encourage new, inactive users to take this activation step as soon as possible. For another example, Hexton points to Dropbox's effective drip campaign that targets users who haven’t downloaded the desktop app and prompts them to install. Vero also breaks down how Trunk Club uses automated emails to reach out to unengaged trial users and put the premium service at top of their mind.

4. Abandoned Shopping Carts
Online clothing retailer Gilt delivers automated drip emails to users who put an item in their cart but did not buy it. But with an automated drip campaign, you can re-engage those waivering customers and lead them back to the «buy» button. Whenever users leave an unpurchased product in their cart, use a drip to follow up and confirm that it is still available. Your drip emails then have a pretty good chance of closing the sale. According to Sale Cycle, abandoned cart emails average a 46.1% open rate, a 13.3% click rate, and $5.64 per email in extra revenue. Shopify also broke down 13 well-designed abandoned cart emails.

5. Recommendations
With that info, they can send you targeted drip emails that contain products or coupons specific to your purchasing tendencies. They could even recommend your favourite K-cup flavour just about when they think you will run out of it, making a sale almost guaranteed. Vero dissected Airbnb's automated emails that go out based on your browsing habits and found that when Airbnb knows more about where you want to travel, its emails get more personal, and in turn more useful. You do not need to be a billion-dollar business to put that knowledge into action, though. Try targeting user segments with drips based on which aspects of your service they use most, or what kinds of content they are most interested in. It is easy to see why Amazon and others put so much work into their recommendation’s emails, especially when you look at the potential returns.

6. Renewals
Whether your user extended their subscription, or it is about to run out, you can leverage drip campaigns to engage customers during the renewal process. You can load these notification emails with contact information for your customer care team, or links to pages where users can update their billing or shipping information. If your subscriptions do not auto renew, craft your drip campaign with a clear call to action, prompting users to re-up with your service.

7. Confirmations
Fairfield uses drip campaigns to confirm user reservations and show off some of the hotel amenities. You have closed the sale, or better yet, convinced a user to stick with your product for another year with a renewed subscription. It should be a no-brainer to send your users an email receipt after they make a purchase, but you can also leverage that communication with related products and upsells. And with confirmations for things like plane tickets and hotel rooms, send a quick email a day before the event to put any important confirmation codes at the top of the user's inbox.
Besides if you do have any questions give me a call: https://clarity.fm/joy-brotonath