Why did my email open rates drop significantly in the US segment this Tuesday?
Michael Ko
Co-founder & CEO, Suped
Published 9 Aug 2025
Updated 13 Oct 2025
7 min read
Seeing a sudden, significant drop in email open rates, especially confined to a specific geographic segment like the US, can be alarming. It’s particularly puzzling when other segments maintain their usual engagement levels. This kind of localized dip points towards specific factors at play within that region, rather than a universal issue with your email content or list quality.
When the US segment, which typically shows strong engagement, suddenly drops by a substantial percentage, it’s important to dive deep into potential causes. This isn't just a minor fluctuation, but a clear signal that something specific may have impacted your recipients' ability or willingness to open your emails.
We've experienced similar situations where external events, like a hurricane and associated power outages, directly led to a massive decrease in opens. While that explains one scenario, a repeat drop on a specific Tuesday, without an obvious natural disaster, requires a different line of inquiry. It suggests a confluence of factors, some perhaps less apparent but equally impactful on recipient behavior.
Considering external factors and audience behavior
A crucial first step when open rates plummet in a particular region is to consider external events. The US is a vast country, and regional or national events can significantly influence how and when people engage with their inboxes. For instance, national holidays, even if they fall later in the week, can shift email engagement patterns earlier in the week as people prepare for time off.
Beyond holidays, significant social, political, or economic events can divert attention. Major news cycles, protests, or other widespread disruptions can make people less inclined to open promotional or even informational emails, especially if the content isn't directly related to these pressing issues. Even topics that seem innocuous, like an SEO guide, might be overlooked when national attention is focused elsewhere.
Seasonal shifts also play a role. The beginning of a new month, especially around a holiday weekend like Labor Day, often brings changes in routine. Kids returning to school, end-of-summer activities, or even major sporting events like the NHL playoffs can impact when and if people check their emails. It's about understanding the broader context of your audience's daily lives.
Moreover, if your audience includes business owners and freelancers, their work patterns might be affected by these external factors. For example, some might be taking extended weekends or prioritizing urgent matters over non-critical emails. These behavioral shifts, when widespread, can collectively lead to a noticeable drop in open rates for a specific segment.
Technical checks and deliverability issues
Investigating Mailbox Provider Performance
When you see a significant drop in opens for a specific segment, it’s critical to analyze the performance across different mailbox providers within that segment. If Gmail distribution dropped from 62% to 47% of all US opens, it suggests a problem specifically with Gmail recipients in that region. This can be due to various reasons, from increased spam filtering to specific updates on Gmail's end. Monitoring your DMARC reports for Google and Yahoo can provide valuable insights into deliverability issues.
Spamhaus Issues: While a brief Spamhaus issue could affect some deliverability, major mailbox providers like Gmail typically use such blocklists as references, not as sole decision-makers. So, it's unlikely to be the primary cause for a sustained or significant drop.
Sender Reputation: Your domain reputation can be impacted, leading to emails being filtered to spam or junk folders, thereby decreasing visibility and opens. This can happen even if your inbox placement is fine according to basic checks.
Engagement Metrics: Beyond opens, it's worth checking if click-through rates (CTR) were also impacted to a similar degree. If CTR also dropped, it suggests broader engagement issues, possibly related to content relevance or inbox placement. Consider tools like Google Postmaster Tools to diagnose these issues.
A sudden drop in email open rates in a specific geographic region like the US can often be attributed to a shift in mailbox provider filtering or reputation changes. While your overall sender reputation might be strong, specific regional ISPs or even local filtering rules could be impacting delivery to that particular segment.
It’s also worth investigating if any specific email authentication failures occurred predominantly for US recipients. For example, if there were temporary issues with SPF, DKIM, or DMARC records that affected US-based mail servers or specific large providers in the region, this could lead to emails being sent to spam (or blocklisted). Monitoring your blocklist status is a good proactive step.
Using an email deliverability tester can help identify if your emails are encountering issues with major US email providers specifically. This can pinpoint if the problem lies with authentication, content, or other technical factors that might be affecting only a segment of your list due to their geographical location.
Investigating ESP performance and infrastructure
It’s also important to confirm if your ESP (email service provider) or multiple ESPs you're using had any specific issues affecting the US segment. While unlikely for both GetResponse and Mailchimp to have simultaneous, US-specific outages, it's not impossible if they share common infrastructure or rely on the same regional data centers that experienced connectivity problems. Contacting their support teams could provide insights.
Even if the issue isn't a full outage, temporary network congestion or routing problems localized to the US could impact email delivery times, potentially leading to lower opens. Emails might be delayed, causing them to arrive at a less optimal time when recipients are no longer actively checking their inboxes.
Also consider that some ESPs might have recent policy changes or updates that inadvertently affect delivery to specific regions or mailbox providers more than others. Keeping abreast of any announcements from your ESP regarding deliverability can sometimes offer clues to sudden shifts in performance.
Localized audience behavior and content perception
Re-evaluate audience context
Socio-political climate: Assess if current events in the US might be affecting your audience's emotional availability for your content, even if it's not a 'heavy' topic directly. People may simply be less engaged with non-essential communications.
Long weekends and holidays: Even days before a major holiday weekend like Labor Day can see reduced engagement as people plan for time off or are already disengaged from work-related emails.
Device usage shifts: Consider if a significant portion of your US audience primarily checks emails on mobile devices, and if a localized event (like curfews or power cuts) would impact that behavior.
ISP breakdown: Analyze opens by ISP within the US. If the decline is heavily concentrated in one or two major ISPs, investigate potential deliverability issues with them specifically.
Historical comparison: Compare this Tuesday's performance to previous Tuesdays that fell around similar dates or holiday periods in past years to identify cyclical patterns.
It’s easy to assume the problem lies with email content or subject lines when open rates drop. However, if your content and subject lines are performing normally in other segments with the same audience profile, it suggests the issue is external to the message itself. This makes the geographic specificity of the US decline even more telling.
The consistency of your open rates (20K in the US, 35K in Europe, 3K in Asia) until this particular Tuesday provides strong evidence that a new variable has been introduced solely for the US segment. This reinforces the need to look beyond generalized marketing issues and focus on factors unique to the US at that specific time.
Given that your audience includes small business owners, SEO experts, and freelancers, their attention might be particularly susceptible to local or national distractions that pull them away from their inboxes. They might be prioritizing news, family, or personal safety over catching up on industry guides during turbulent times, as some sources suggest.
Concluding thoughts on open rate declines
Pinpointing the exact reason for a significant drop in email open rates within a specific segment on a particular day is like solving a puzzle with many pieces. It rarely comes down to a single factor. More often, it's a combination of external events, mailbox provider behavior, and shifts in audience priorities that culminate in reduced engagement.
Maintaining a healthy sender reputation and robust email authentication are ongoing efforts that help mitigate risks, but some factors remain beyond direct control. Continuous monitoring of your deliverability metrics, especially through DMARC reports provided by Suped, is key to catching these issues early and responding effectively.
While we cannot change macro-level events or human behavior, we can certainly optimize our email strategy. This includes segmenting audiences more precisely, tailoring content to current events where appropriate, and adjusting sending schedules to align with expected audience availability.
Views from the trenches
Best practices
Monitor for regional or national news that could impact email engagement.
Segment your audience further if geographical distribution within a country is uneven.
Cross-reference open rate drops with known local events or holidays.
Analyze engagement by mailbox provider within the affected segment to identify specific issues.
Common pitfalls
Assuming content or subject line is always the culprit for regional drops.
Overlooking broader socio-political or environmental factors impacting an audience.
Failing to check if multiple ESPs share infrastructure vulnerable to regional outages.
Not having sufficient geographical breakdown in reporting to pinpoint exact affected areas.
Expert tips
Use DMARC reports to analyze deliverability by sending source and recipient domain.
Leverage audience insights to predict periods of reduced engagement for specific segments.
Consider A/B testing sending times or subject lines for affected segments during recovery.
Always verify if click-through rates also suffered a similar decline, as this indicates overall engagement issues, not just opens.
Marketer view
Marketer from Email Geeks says that coming into a long weekend like Labor Day can shift email engagement patterns, even if the actual holiday is later in the week.
August 31, 2020 - Email Geeks
Expert view
Expert from Email Geeks suggests that while external factors are possible, it's more inclined to look at mailbox provider distribution, the ESP being used, and the frequency and message content.
Gmail distribution dropped from 62% to 47% of all US opens, it suggests a problem specifically with Gmail recipients in that region. This can be due to various reasons, from increased spam filtering to specific updates on Gmail's end. Monitoring your DMARC reports for Google and Yahoo can provide valuable insights into deliverability issues.
Gmail typically use such blocklists as references, not as sole decision-makers. So, it's unlikely to be the primary cause for a sustained or significant drop.
GetResponse and 
Mailchimp to have simultaneous, US-specific outages, it's not impossible if they share common infrastructure or rely on the same regional data centers that experienced connectivity problems. Contacting their support teams could provide insights.
