Bad timing is a real, fixable problem—and Monday morning or Friday afternoon are genuinely the worst slots you can pick. But the fix isn't as simple as "always send on Tuesday." The data is more nuanced than that, and getting it right depends on your industry and audience.
Another common blunder that's easy to overlook: ignoring time zones entirely. If you're in Chicago hitting send at 9am but half your list is in London, that's 2pm their time—completely different engagement behavior. Always schedule in your recipients' local time zone.
What the data actually says about the best day
Klaviyo's 2023 analysis of thousands of email campaigns—filtered to remove machine opens and capture actual human engagement—found that Wednesday and Thursday are the best days to send emails across industries. That's the headline finding, and it's the safest starting point if you don't have your own A/B test data yet.
That said, industry vertical matters a lot. When Klaviyo sliced the data by sector, Tuesday emerged as the top day for open rates in several specific niches:
- Health & beauty: Tuesday had the best open rates (12.05%), with Wednesday delivering the best click-through rates (1.63%)
- Apparel & accessories: Highest open rates on Tuesday (11.17%), best click rates on Wednesday (2.20%)
- Food & beverage: Best open rates on Tuesday (13.67%), best click rates on Friday (2.33%)
- Home & garden: Best open rates on Tuesday (11.65%), best click rates on Wednesday/Thursday (2.08%)
- Jewelry: Thursday is the top day for both open rates (11.20%) and click rates (1.92%)
The pattern that holds almost everywhere: mid-week is where the opens live, and Wednesday and Thursday anchor that window overall. Tuesday is legitimately strong in several verticals, but it's not a universal winner—so if someone tells you "just always send on Tuesday," they're oversimplifying.
Worth noting: Klaviyo is a vendor with a commercial interest in send-time optimization tools. Their data comes from their own customer base, which skews toward ecommerce. Use it as a strong directional guide, and validate against your own audience through A/B testing.
What time of day?
The general consensus across email platforms is mid-morning—roughly 9am to 11am in your recipient's local time zone. This is when professionals are settling into their workday and doing their first real inbox check. Mailchimp's Send Time Optimization system is designed specifically to analyze individual subscriber behavior and deliver at the moment each person is most likely to open, rather than applying a single fixed time to your whole list.
GetResponse's 2024 Email Marketing Benchmarks report—based on analysis of more than 4.4 billion messages sent in 2023—found an average email open rate of 39.64% and an average click-through rate of 3.25% across all industries. Those are your baseline numbers: if you're sitting significantly below them, timing is one of the levers worth pulling.
The practical takeaway
If you need a starting point right now: schedule for Wednesday or Thursday morning, around 10am in your recipient's local time zone. That's what Klaviyo's cross-industry data supports. If you're in a Tuesday-skewing vertical like food & beverage or health & beauty, test Tuesday against Wednesday and let your own data settle it.
What you should stop doing immediately: sending whenever you finish writing. That's how you end up in Monday morning inbox chaos or Friday afternoon when everyone's already mentally checked out.