What is the origin of the best time to send emails and how does it affect recipients?
Matthew Whittaker
Co-founder & CTO, Suped
Published 8 May 2025
Updated 16 Aug 2025
7 min read
For years, the phrase "Tuesday at 10 AM" has been whispered as the magic hour for sending emails. It's almost become a mantra in email marketing circles, cited in countless articles and presentations as the undisputed best time to hit send. This advice has been so widely accepted that it feels like an undeniable truth, passed down through generations of marketers.
But where did this idea actually come from? Was it the result of rigorous scientific study, analyzing billions of email interactions across diverse audiences? Or is it something else entirely, perhaps a self-fulfilling prophecy born from the early days of digital marketing that has simply persisted through sheer repetition?
In this article, I'll delve into the curious origin of the "best time to send" myth, explore how it might actually influence contemporary data, and, most importantly, explain why focusing on your individual recipients is far more crucial than adhering to a one-size-fits-all timestamp for your email campaigns.
The enduring myth of universal send times
The "Tuesday at 10 AM" phenomenon traces its roots back to the nascent days of commercial email, particularly the late 1990s and early 2000s. In an era before sophisticated analytics and personalized send-time optimization tools, marketers relied on rudimentary data and anecdotal evidence. Early email marketing newsletters and conferences began to share insights, and certain patterns emerged, like high engagement on Tuesday mornings.
This early data was often limited in scope and highly susceptible to sampling bias. If the early adopters of email marketing predominantly sent their campaigns on Tuesday mornings, then, naturally, the highest engagement would be observed during those times. Companies like ExactTarget (now part of Salesforce) and other early email service providers likely contributed to popularizing these findings through their own research and recommendations.
The problem is that this initial observation, while perhaps true for its time, became a self-fulfilling prophecy. Because marketers believed Tuesday mornings were best, they continued to send during those hours. This ongoing behavior then skewed all subsequent datasets. For example, a 2013 study from MarketingCharts and more recent 2022 research by GetResponse might still indicate peak engagement during these times, but it's largely because more emails are simply sent then, not necessarily because recipients are inherently more receptive.
Factors truly affecting recipient engagement
Instead of chasing a mythical best time, a truly effective email strategy focuses on the nuances of your specific audience. Recipient behavior is highly individual and influenced by numerous factors. What works for a B2B audience during business hours might fall flat for a B2C audience on a weekend. Time zones also play a significant role, as a "10 AM send" in New York is very different for someone in Los Angeles or London.
Different types of emails also prompt different recipient behaviors. A transactional email (like an order confirmation) will likely be opened immediately regardless of send time, whereas a promotional email or newsletter might compete for attention when a recipient has downtime. For newsletters, establishing a consistent cadence can be more effective than trying to hit a perceived optimal window, as recipients learn to expect your content.
Ultimately, the effectiveness of your email campaign hinges on delivering relevant messaging when your particular readers are most likely to engage. This requires moving beyond broad generalizations and adopting a data-driven approach tailored to your unique subscriber base.
Generic advice
Universal timing: Suggests one best time (e.g., Tuesday at 10 AM) applies to all campaigns and audiences.
Simple benchmarks: Relies on aggregated industry data which may not reflect your specific niche.
Recipient agnostic: Ignores individual subscriber habits, time zones, and preferences.
Recipient-centric approach
Audience segmentation: Tailors send times based on demographic, geographic, and behavioral segments.
Historical engagement: Leverages past open and click data to identify personalized optimal times.
Continuous testing: Implements ongoing A/B tests to refine timing strategies for different campaign types.
The impact of sending practices on deliverability
While send time might not directly land you on a blacklist, your overall sending practices, including timing and volume, profoundly impact your sender reputation and, consequently, your email deliverability. Internet Service Providers (ISPs) like Google and Microsoft monitor sending patterns for anomalies.
If you suddenly blast a massive volume of emails during a perceived "best time" without gradually scaling your sends or if your previous sends have resulted in low engagement, high spam complaints, or bounces, you could face deliverability issues. This is because ISPs look for consistent, predictable sending behavior that indicates a legitimate sender, not sudden, sporadic spikes that can resemble spam.
Poor email sending practices can cause your messages to be routed to spam folders or even lead to your IP or domain being added to a blocklist. Maintaining a healthy domain reputation is paramount, and this involves much more than just the clock on the wall. Factors like content quality, list hygiene, and proper authentication (SPF, DKIM, DMARC) contribute far more to inbox placement than a specific send time.
Deliverability considerations beyond time
While finding the "best time" for your audience is important for engagement, it's critical not to overlook foundational deliverability factors. These elements directly impact whether your email even makes it to the inbox, regardless of when it was sent.
The most effective strategy for optimizing email send times is not to follow generic advice, but to embrace a data-driven, iterative approach. Your own historical data holds the key to understanding your specific audience's behavior. Analyze when your subscribers are most engaged by tracking metrics like open rates, click-through rates, and conversions.
A/B testing is an invaluable tool here. Experiment with different send days and times for segments of your audience. For example, you could test morning versus afternoon sends, or mid-week versus weekend sends for specific campaign types. Over time, these tests will reveal patterns unique to your subscriber base, allowing you to refine your strategy for maximum impact and improve your overall email deliverability.
Many modern email marketing platforms offer advanced features like AI-powered send time optimization. These tools can analyze individual subscriber behavior and automatically deliver emails when each recipient is most likely to engage, often taking into account time zones and past interaction history. Leveraging such features can significantly boost your email click-through rate and overall campaign performance.
Metric
Why it matters
How to measure
Open rate
Indicates initial interest and subject line effectiveness. Essential for A/B testing variations.
Track % of recipients who open your email. Compare this across different send times.
Click-through rate (CTR)
Measures how many recipients clicked on a link. Reflects content relevance and call-to-action strength.
Monitor % of recipients who clicked a link in your email. This often provides a deeper insight than opens alone.
Conversion rate
The ultimate measure of success for sales, sign-ups, or other goals. Connects email to business outcomes.
Track % of recipients who completed a desired action after clicking. This is tied to your campaign's ultimate objective.
Views from the trenches
Best practices
Continuously A/B test your send times with different audience segments.
Prioritize email content relevance over rigid adherence to popular send times.
Monitor individual recipient engagement patterns to personalize delivery times.
Avoid sending high volumes during universal 'peak' times to prevent inbox saturation.
Common pitfalls
Relying solely on outdated or generalized 'best time to send' studies.
Neglecting to segment your audience based on their unique time zones and habits.
Assuming that higher send volume at a specific time equates to better engagement.
Failing to account for the content type when determining optimal send schedules.
Expert tips
Utilize advanced analytics to track engagement beyond just open and click rates.
Consider using adaptive sending features offered by modern email platforms.
Regularly review your email list health to ensure sustained deliverability performance.
Experiment with sending at unexpected times to stand out in a crowded inbox.
Marketer view
Marketer from Email Geeks says the conventional wisdom about email send times dates back to the early days of the internet, with references to welcome emails from services like AOL in the late 1990s.
Feb 13, 2023 - Email Geeks
Marketer view
Marketer from Email Geeks says modern studies often show higher engagement on Tuesday mornings not because it's truly optimal, but because marketers are already sending more emails during that time, skewing the data.
Feb 13, 2023 - Email Geeks
Redefining email send strategy
The notion of a single "best time to send emails" is largely a historical artifact, perpetuated by self-reinforcing data. While convenient, it oversimplifies the complex dynamics of email engagement. True optimization comes from understanding your unique audience, their habits, and the specific context of your messages.
By moving beyond the myth and focusing on data-driven testing, audience segmentation, and the overall health of your sending practices, you can dramatically improve your email performance. The best time to send an email isn't a fixed point on a calendar; it's a dynamic variable you discover and continuously refine through thoughtful experimentation and a deep understanding of your subscribers.
ExactTarget (now part of 
Salesforce) and other early email service providers likely contributed to popularizing these findings through their own research and recommendations.
Google and 
Microsoft monitor sending patterns for anomalies.
AI-powered send time optimization. These tools can analyze individual subscriber behavior and automatically deliver emails when each recipient is most likely to engage, often taking into account time zones and past interaction history. Leveraging such features can significantly boost your email click-through rate and overall campaign performance.
