Best Time to Send Email: What the Data Says (and When to Ignore It)

There is no universal best time to send email. Large sender studies tend to favor weekdays, with opens clustering in the morning (roughly 8 to 11 a.m.) in the recipient’s local time, but the studies disagree on the best day, the best hour, and even whether mornings win for clicks. B2B audiences are the most weekday-bound. One more caution: since Apple Mail Privacy Protection arrived in 2021, any ranking built on open rate is less reliable than one built on clicks or conversions. Use the studies below as a starting hypothesis, then let your own test decide. Triggered and lifecycle email should skip the clock entirely and send when the event happens.

What Five Send-Time Studies Found

Each row below comes from the publisher’s own page, with the data basis and metric as that publisher states them. The numbers are not comparable across rows, so they are not averaged here.

Source	Published	Data basis	Metric	Best day	Best time
Omnisend	May 2026	26 billion marketing emails over 12 months, sent by ecommerce brands on Omnisend	Opens, clicks, conversions	Tuesday for opens (31.27%) and clicks (0.81% of sent); Friday for conversions (0.081%)	Opens 9 to 11 a.m.; clicks around 7 to 8 a.m. with a lift at 4 p.m.; conversions peak Friday 7 a.m.
MailerLite	Dec 2025 (updated Jun 2026)	2,138,817 campaigns, Dec 2024 to Nov 2025, US, UK, Australia, Canada	Opens, clicks	Friday at 6 p.m. stands out (49.7% opens, 8.09% clicks)	Opens 8 to 11 a.m. local; clicks mostly 8 to 9 p.m. on weekdays
Brevo	Feb 2025	“Hundreds of emails from the top ecommerce companies”	Open and click volume, open rate, CTR	Tuesday and Thursday for opens; Tuesday and Wednesday for clicks	10 a.m. and 3:30 p.m.; software/SaaS: 2 to 3 p.m.
Klaviyo	Jul 2024	“Thousands” of 2023 campaigns, machine opens removed	Opens, clicks, placed orders	Wednesday (12.49% opens, 2.18% clicks) and Thursday (12.43%, 2.13%)	No single best hour reported
GetResponse	2020 study (page updated Jan 2026)	Over 2.85 million emails, first two quarters of 2020	Opens, CTR, click-to-open	Friday for opens (20.58%); Tuesday for clicks (2.33%)	4 a.m. for opens, 6 a.m. for clicks (global)

Two things stand out. First, the winning day changes with the metric inside a single study: Omnisend’s best day for opens (Tuesday) is not its best day for conversions (Friday), and GetResponse’s best day for opens (Friday) is not its best for clicks (Tuesday). Second, the margins are small. Klaviyo’s Wednesday and Thursday open rates differ by about 0.06 percentage points. Klaviyo itself writes that “historical data isn’t a reliable way to determine the best email send days.”

The honest short answer: weekday mornings in the recipient’s time zone are a reasonable default, and Tuesday through Thursday shows up most often. But the best day moves with the metric, the audience and the year, and the gap between good and bad days is often a fraction of a point.

Why the Studies Disagree, and What Apple Mail Privacy Protection Did to Open Data

The studies disagree for four reasons that have nothing to do with email being random:

• Different senders. Omnisend’s data comes from ecommerce brands. MailerLite reports separate results for creators, SMBs, institutions and ecommerce. Brevo splits its results by business type.
• Different metrics. Opens, clicks, click-to-sent rate and conversions each crown a different slot.
• Different periods. GetResponse’s data is from early 2020, before Apple changed how opens are counted.
• Different clocks. A “10 a.m.” slot means very different things depending on whether it is the sender’s time zone or the recipient’s.

The measurement problem is the biggest. Apple’s Mail Privacy Protection page says that Protect Mail Activity downloads remote content “in the background by default” and “regardless of whether you engage with the email.” Without it, Apple notes, email senders “may learn when and how many times you opened their email.” Because the tracking pixel loads whether or not a person reads the message, the open is recorded when Apple fetches the content, not when someone reads it. Postmark described the consequence in November 2021: you could “potentially see a 100% open rate for your Apple Mail recipients” whether or not they open the message.

The MPP caveat: for recipients using Apple Mail Privacy Protection, an “open” is logged when Apple’s servers preload the message, not when a person reads it. Send-time rankings based on open rate therefore partly measure when Apple fetched content, so clicks and conversions are the safer metrics.

Klaviyo is the only study in the table that says it removed machine opens. For the others, the publisher’s page does not say how Apple-preloaded opens were handled, so treat their open-rate rankings with extra caution. Clicks are not affected the same way: Apple’s proxy loads content but does not click links on a person’s behalf.

B2B SaaS vs B2C: How Work Hours Change the Answer

B2B audiences are the most tied to the working week. Brevo’s breakdown is the clearest published split: for professional services (B2B) it found Monday or Tuesday from 8 to 10 a.m., and for software/SaaS Tuesday or Thursday from 2 to 3 p.m. Those are two different B2B slots, so “send B2B email in the morning” is already an oversimplification.

For consumer-facing brands the evidence is more varied. Omnisend found Saturday was its weakest day, with “the lowest click-to-sent rate at 0.68% and the lowest conversion rate at 0.058%.” Klaviyo found that sporting goods was the exception where Sunday gave the best click rate (2.79%), while for automotive and electronics, weekday sending beat weekends. Weekends can work for some consumer categories, but the published data supports that only vertical by vertical.

If your list is mostly work addresses, expect weekday behavior and test two windows: early in the workday and mid-afternoon.

Newsletters, Campaigns and Lifecycle Email Need Different Rules

Newsletters: consistency matters more than finding the perfect slot. Readers who expect your issue on a given weekday are more useful to you than a marginally better hour that changes monthly. Pick a window from the evidence above, hold it for several issues, and judge it on clicks.

One-off campaigns: treat send time as a test variable. A product announcement or webinar invite is the right place to compare two windows.

Lifecycle and transactional email: do not schedule these by clock. A welcome message, password reset or trial-ending reminder is most useful at the moment of the event. Triggered emails should fire on the trigger, with optional quiet hours if a message is not urgent and the recipient’s local night would make it feel intrusive. Our guide to lifecycle automation covers where timing rules belong in a flow. Drip campaigns sit in between: each email waits a fixed delay after the person’s entry event, so their timing is about spacing between emails rather than a weekly slot.

Time Zones and Send-Time Optimization

Mailchimp’s send-time research page (undated) puts the best newsletter time at 10 a.m. “in the recipients’ own time zones,” which is a different instruction from 10 a.m. on the sender’s clock. If your list spans regions, sending at one clock time means some people get the email at 4 a.m. and others at mid-afternoon. Most platforms offer local-time delivery for this reason.

Send-time optimization (STO) goes one step further and picks a time per contact from that person’s past behavior. Two vendor docs show the shape of it:

• Mailchimp says STO “can be used if there is enough data from your sent emails for us to calculate an optimal send time,” and notes it is not available for automated emails.
• MailerLite’s best send time detection is based on each subscriber’s “peak open or click times,” applies to campaigns with 1,000 or more subscribers, and nudges a small share of sends earlier or later to learn from responses.

The common requirement is history per contact. A new list, or one with few engaged readers, gives these features little to learn from. Also check which signal the feature optimizes. If it optimizes for opens, Apple Mail users will confuse it.

How to Find Your Own Best Send Time

Klaviyo’s advice is to rely on A/B testing instead of historical benchmarks, and Omnisend’s is to start from the outcome you want. A usable test looks like this:

1. Pick one variable. Change send time only. Same subject line, content, sender name and offer for both arms. (If you also want to test subject lines, run it as a separate test; our guide on A/B testing subject lines covers the method.)
2. Randomize the split. Assign contacts to arms at random from the same list, not by signup date or region.
3. Fix the clock basis. Use local time for each recipient in both arms, or you are testing time zones, not hours.
4. Give each arm enough recipients. Small arms produce winners that are noise. Rather than trusting a rule of thumb, check whether your result would flip if you reran it.
5. Judge on clicks or conversions, not opens. Use click-through rate or conversion rate as the deciding metric, because opens are partly Apple’s preloads.
6. Repeat across weeks. One send can be thrown off by a holiday, a product launch or a news cycle. A pattern that holds across several sends is worth keeping.
7. Re-test periodically. Audience habits and mailbox providers change; the studies above span 2020 to 2026 and do not agree.

The “clicks, not opens” rule: to compare two send times, split the same list at random, change only the time, and pick the winner on clicks or conversions across several sends. Opens are unreliable after Apple Mail Privacy Protection because Apple preloads the message regardless of whether anyone reads it.

Frequently Asked Questions