Picture this: It’s the mid-2000s, and a marketer schedules a big email campaign for 10:00 AM on a Tuesday. Conventional wisdom says this is the golden hour, as by then, people have settled at their desks with a cup of coffee, and your email will pop up right as they check their morning inbox.
For years, mid‑morning on a mid‑week day (often Tuesday or Thursday) was hailed as the prime time for marketing emails and it made sense. In the early days, email was largely a 9‑to‑5 affair, something many of us checked at work or on our computer during lunch breaks, but rarely beyond that.
Marketers learned to time their “email blasts” to align with these routines, hoping to catch people when we were most receptive. So, are Tuesday mornings still the window you should be sending in? After all, the best time to send emails has changed over the years…
When mid‑morning ruled the inbox (the early days)
In the late 1990s and early 2000s, email itself was exciting and new for the general population. Pre-smartphone, most people accessed email on desktop computers. Think back to those days of logging on to Outlook or Lotus Notes (!) on your office PC.
Naturally, weekday mornings quickly emerged as a sweet spot for marketing emails. By mid-morning on a workday, people had sifted through any urgent messages and were open to browsing a newsletter or promo in their inbox.
This is when the industry solidified around Tuesday through Thursday, around 10 AM as the ideal send time for many campaigns. Hitting send just as the workday started was thought to maximise the chances of messages being read.
Marketers in this era took the cue. Email schedules became rather predictable: avoid the Monday madness and Friday fade-out, and aim for the mid-week, mid-morning window. And for a while, it worked. With most people following a similar work routine across the UK, commutes in the morning, desk work by 9 AM, lunch around 1 PM, off by 5, the timing of email engagement was relatively predictable. The “best time” to send a marketing email was treated almost like a universal truth. It was a bit like broadcast television: there was a prime time when everyone was tuned in.
However, nothing stays static, not our inboxes, and certainly not our daily habits. By the late 2000s, a quiet revolution was buzzing in our pockets.
The smartphone shake-up: email around the clock
The launch of the BlackBerry and later the iPhone changed everything. Suddenly, email was no longer bound to a clunky computer; it was with us everywhere, all the time.
91% of people were checking their email at least once a day on their phones by the mid-2010s. The inbox became a constant companion, dinging in our pockets whether we were on the train, in a queue at Pret, or on the sofa at home.
This always-on connectivity led to new email habits. Instead of a single morning inbox check, many people began glancing at emails throughout the day (and night). A study by Deloitte found that 89% of consumers check their phone within the first hour of waking up, and 82% check it before sleep, a clear sign that email had seeped into morning and bedtime routines.
It suddenly became common to glance over emails during the daily commute or while watching TV in the evening. The result? Those rigid “prime times” started to blur. Early morning, lunch hour, evening, all became fair game for grabbing a reader’s attention.
Marketers started to take notice of these shifts in consumer behaviour. Some adventurous brands started experimenting with evening sends for consumer emails, reasoning that shoppers might be more relaxed and click-happy after work. In fact, UK consumer inboxes became most active in the evenings, roughly 8 to 10 PM, when people unwind and catch up on personal emails at home.
Rather than only chasing the 10 AM slot, marketers saw that a well-timed message at 8 PM (“e.g flash sale until midnight!”) could perform well if it was caught at the right moment. This was a stark change from the early 2000s, when sending a marketing email at 9 PM would’ve seemed pointless (who was checking email that late?).
At the same time, the B2B world also felt the tremors from smartphones. Yes, professionals still had a rush of emails each morning, but now they might also skim work emails on their phone over dinner. The boundaries between work and personal time grew fuzzier.
By the late 2010s, the question wasn’t “What single time is everyone checking email?” but rather “How do we reach people who are constantly checking, but at different times?” Email was no longer a one-time daily ritual, it was woven throughout the day.
The Work-from-Home Revolution and New Routines
Just when marketers thought they had adapted to the mobile era, the world changed again, and this time dramatically. The 2020s (ushered in by the COVID-19 pandemic) saw an unprecedented shift towards remote work and flexible schedules.
In many countries, millions began working from home, obliterating the traditional 9-to-5 routine and the daily commute that had defined email patterns for decades. No more train rides where commuters thumb through emails on the 8:07 to Old Street; no more strict separation of “office hours” versus personal time. Work and home life merged, and so did users' communication habits.
During the pandemic’s early phase, companies noticed changes in when people engaged with emails. The old benchmarks went out the window. The Email Uplers study noted that previously “ideal” send times, like early Tuesday morning, lunchtime, or rush-hour commute windows, suddenly weren’t so ideal anymore.
Without a commute, that pre-9 AM window lost its captive audience. Many people enjoyed a bit more sleep or dove straight into work tasks at home, checking emails at odd intervals instead of a set time. And with flexible working emerging, some people took afternoon breaks and caught up on email in the late afternoon or evening instead.
Interestingly, data from recent years started to show higher engagement in late afternoon and after-work hours on weekdays. By 2025, one study found that on weekdays the highest email open rates often occur between 3 PM and 7 PM.
And because so many were (and still are) home all day, weekdays and weekends started to feel a bit more alike. It’s no surprise that weekend email engagement also climbed for some audiences during this period. If you’re on the sofa on a Sunday and your phone pings with an interesting newsletter or offer, why not open it?
In fact, even though far fewer marketing emails go out on weekends, the ones that did saw surprisingly decent open rates. It seems that with more flexible schedules, consumers engage with emails on their own terms, whenever they have a free moment, regardless of what the old “rules” say.
No One-Size-Fits-All: How Marketers Adapted Over Time
Faced with these shifts in consumer behaviour, email marketers had to evolve their strategies. The story of the past 15+ years had been a gradual loosening of the rules and a turn towards more intricate tactics:
- From Universal to Personalised Timing: In the early days, marketers treated send-time as a one-size-fits-all decision, find the one best time and blast everyone then. Today, we know there’s no single universal best time. In fact, about half of marketers now acknowledge that a “perfect” time varies by audience or individual.
The optimal moment to email depends on whom you’re targeting. A busy working mum might check emails at 9 PM once the kids are in bed, whereas a young professional might browse their inbox with morning coffee at 7 AM. Rather than forcing both into a 10 AM mold, smart marketeers adapt to each segment’s rhythm.
Rise of Send-Time Optimisation: As behaviour diverged, companies started leveraging technology to hit the right timing for each recipient. Platforms rolled out features to automatically send an email at the user’s own optimal time.
Instead of guessing, these tools analyse when each subscriber tends to open emails and then schedule messages accordingly. For example, if John usually opens emails late at night and Jane opens in the morning, an automated system can send the same campaign to John at 9 PM and Jane at 9 AM.
- Continuous Testing & Flexibility: Marketers also learned not to put all their eggs in the “Tuesday 10 AM” basket. Over the years, they’ve become more experimental with send times.
A/B tests might be run to compare, say, a morning send vs. an afternoon send for the same email, or weekday vs. weekend. Often, these tests bring surprises, your audience could be more responsive on Sunday evening than Wednesday morning, depending on their lifestyle.
The key lesson has been to know your audience, meet your readers when they are ready, not just when it’s convenient for you.
- Navigating the Noise: An unintended side effect of everyone clinging to the old best-time rules was inbox crowding. Remember that perfect 10 AM Tuesday slot? By the 2010s, everyone was sending at that time, and users’ inboxes were swamped. Marketers had to get creative to stand out.
Some started sending at more random times like 10:47 AM or 2:13 PM, deliberately off-peak, to avoid the rush of emails all hitting at once. Others targeted less congested days (like trying a Saturday send) to see if their email would shine when fewer messages compete for attention.
The Evolution Continues: What’s Next?
The journey of the “best time to send an email” is a bit like a living timeline of our digital lifestyles. As consumers, our relationship with email has shifted from a scheduled, almost ritualised activity (“I check my emails every morning at work”) to a, always-with-us background presence in our lives. And marketers have evolved right alongside this.
As our lives change, so do our inbox habits. One thing’s for sure: email isn’t going away, and neither is the question of timing. But instead of chasing a mythical one-size-fits-all answer, marketers now approach it as an ongoing dialogue with their audience’s routines. Finding the perfect moment to say “You've got mail!” has become less about following an inflexible rule and more about understanding an ever-changing story.
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