Why Timing Is Everything in SMS

Imagine getting a sales text at 11:47 PM. Even if the offer’s great, it feels invasive.

That’s why smart SMS timing matters. If your brand texts too early or too late, you risk being muted, unsubscribed, or worse, reported.

Klaviyo’s SMS Quiet Hours feature is built to protect your brand’s trust. But many DTC teams don’t even know it’s on. This blog shows you how to use Quiet Hours correctly—so you can keep customers happy, stay compliant, and boost engagement.

What Are Klaviyo SMS Quiet Hours?

Klaviyo SMS Quiet Hours pause automated SMS messages during a set time window so your messages don’t go out while people sleep or are offline.

Key Facts:

• Default setting: 8 PM–11 AM (local time of the recipient)

• Applies only to flows (not campaigns)

• Uses area codes and country data to localise timing

• Helps support TCPA and CTIA compliance in the US

Need help with compliance? Check out our guide on Klaviyo Smart Sending for email best practices and how it complements Quiet Hours

Source: Klaviyo

How to Enable and Customise Quiet Hours in Klaviyo

Step-by-Step: How to Turn on Quiet Hours in Sender Preferences

1. Go to Account Settings

   • In your Klaviyo homepage, click on your profile icon (bottom left), then choose Settings.
     
     

2. Navigate to SMS Settings

   • Under Settings > select SMS tab > then click Sender preferences.

     
     

Source: Klaviyo

3. Scroll to Quiet Hours

   • Under Sender Preferences, you’ll see the SMS Quiet Hours settings panel.

     
     

4. Enable Quiet Hours

   • Tick the box labelled “Enable SMS Quiet Hours” to activate the feature across all eligible flows.

Important Note: Klaviyo’s Preview Mode does not simulate Quiet Hours logic. To test accurately, create test profiles in different time zones and trigger flows manually. You can find more on this in our testing section.

Choosing a Start/End Time and Setting the Time Zone Logic

Once Quiet Hours are enabled:

• Set your start time (e.g. 8:00 PM) and end time (e.g. 11:00 AM).

• Quiet Hours apply based on the recipient’s local time zone, not your account’s default zone. Klaviyo determines this using country and area code detection.

• The default setting is 8 PM–11 AM, but you can customise this to match your audience's behaviour or regional laws.

  
  

Tip: Avoid setting quiet hours that overlap with your top-performing send times—refer to your past SMS campaign analytics.

How to Toggle Quiet Hours at the Flow Message Level

If you only want Quiet Hours to apply to specific flows or messages:

1. Open a Flow from your dashboard.

2. Click on an SMS block within the flow.

3. Scroll down to the Quiet Hours toggle in the message settings.

4. Enable or disable for that individual message.

   
   

Source: Klaviyo

This is useful if you want exceptions for transactional SMS like order confirmations, but still want promotional texts paused overnight.

If you're building out flows from scratch, you might also want to review our breakdown of 8 Essential Klaviyo Flows to Boost Customer Loyalty to ensure your automation structure is aligned with Quiet Hour logic.

What Happens If a Message Is Triggered During Quiet Hours?

Queued, Not Cancelled

When an SMS is triggered during Quiet Hours, Klaviyo pauses the message and queues it to send once the window ends—nothing is lost.

Only the Message Waits

The flow continues running, but the SMS block is held until the recipient’s local time is back within the sendable window.

Settings Update in Real-Time

If you change Quiet Hour settings while a message is waiting, Klaviyo uses the new settings, potentially sending it sooner or later.

Track “Waiting” Messages

You can view paused messages in Flow Analytics, where each SMS block shows the number of queued messages and when they’ll be sent.

You can also refer to Mastering Klaviyo DTC Reporting & Analytics to dig deeper into how to monitor and optimise paused or delayed messages.

Klaviyo SMS Quiet Hours vs Smart Sending – What’s the Difference?

Klaviyo SMS Quiet Hours and Smart Sending are both tools in Klaviyo to help you avoid annoying your customers, but they work in different ways.

• Quiet Hours stops SMS messages from sending during set hours (default: 8 PM–11 AM).

• Smart Sending avoids sending too many messages in a short time (default: one message every 16 hours).

How They Work Together

If both are on:

• Klaviyo delays the SMS until Quiet Hours end.

• Then it checks Smart Sending. If another message was sent too recently, it won’t send.

If you're not already using both features, start by reviewing how Klaviyo Smart Sending reduces frequency-based fatigue while Quiet Hours tackles bad timing.

Example: Abandoned Cart Flow

A cart reminder triggers at 10 PM:

• Quiet Hours queues it until 11 AM.

• At 11 AM, if another message went out recently, Smart Sending may hold it back.

  
  

When Should You Override Quiet Hours?

While Quiet Hours help avoid annoying customers, there are times when overriding makes sense—but only with care.

Valid Use Cases

• Flash sales or urgent drops

• Back-in-stock alerts for high-demand items

• 24-hour campaigns where timing is critical

Use overrides only for high-intent segments that are likely to convert.

Legal Watchouts

Avoid overrides in restricted regions like France, Florida, or Germany, where SMS send times are legally regulated.

For time-sensitive flows like flash sales, you can refer to our Mastering BFCM Guide for examples of how to balance urgency and deliverability.

Quiet Hours for Global Brands

Managing SMS timing for an international customer base is tricky, but Klaviyo’s built-in localisation makes it much easier. Here’s how global brands can stay compliant and customer-friendly.

Area Code and Country Detection

Klaviyo automatically detects a recipient’s country and local time zone based on their phone number’s area code. This means you don’t need to manually set time zones for each customer—quiet hours apply based on their local time, not yours.

International Compliance Tips

Every region has its own rules:

• United States: Follows TCPA guidelines (no texts before 8 AM or after 9 PM local time).

• France: Texts cannot be sent on Sundays, before 8 AM or after 10 PM, including public holidays.

• Germany: Requires opt-ins with double confirmation and stricter send-time restrictions.

• Australia & UK: Generally follow GDPR, with strong opt-in and timing rules.

Use Klaviyo’s built-in compliance features and avoid overriding quiet hours in legally restricted regions.

Managing Mixed-Audience Flows

If your flows include contacts from multiple countries, structure them with conditional splits by location or timezone.

Example:

• One branch for “Country is the United States”

• Another for “Country is not United States” with separate send logic

This avoids sending messages at odd hours or violating local laws.

Safe Send Window Strategy

For a simpler setup, use a global “safe window” that covers all regions—e.g. 10 AM to 7 PM local time. It’s not always optimal, but it’s a scalable safeguard if you don’t want to segment by region.

To support list growth in global markets, consider pairing quiet hours with 5 Proven Techniques for Increasing SMS Opt-Ins in Klaviyo for better acquisition before you worry about timing.

Flow Example with Quiet Hours Enabled

Seeing quiet hours in action helps bring the value to life. Below is a practical walkthrough showing how they work in Klaviyo, what changes in user engagement, and why they matter, especially for DTC brands running time-sensitive automations.

Abandoned Cart Flow with Quiet Hours ON

Let’s say a customer abandons their cart at 10:30 PM local time. Instead of firing an immediate SMS and risking a disruption, Klaviyo detects it’s during quiet hours and queues the message.

• The SMS is automatically held.

• It’s delivered at 11:01 AM the next day, when quiet hours end.

• This improves the chance they see the message and take action.

Want more tips on cart recovery? Check out our Klaviyo SMS Abandoned Cart Guide for flow tactics that increase ROI without being intrusive.

Performance Comparison: Quiet Hours ON vs OFF

Brands that enable quiet hours often report:

• Lower opt-out rates (because messages aren’t intrusive).

• Higher click-through rates (sent during alert hours).

• Fewer complaints in reviews or replies.

One example: A DTC skincare brand saw 22% higher CTR when SMS sends were delayed until post-quiet hours vs late-night sends.

Transactional SMS Example

Shipping notifications and order confirmations are often triggered at odd hours by warehouse systems.

With quiet hours ON:

• The message waits until morning.

• Customers don’t wake up to pings at 2 AM.

• For non-urgent info, this delay protects brand trust without harming CX.

Common Mistakes to Avoid

Quiet Hours protect your brand if set up correctly. But many teams slip up. Here’s a quick table of the most common mistakes, why they matter, and how to fix them:

For broader context on SMS and email mistakes, read 15 Email Marketing Mistakes to Avoid When Using Klaviyo. It includes both strategy and deliverability pitfalls.

How to Preview and Test Quiet Hour Logic

Setting up Klaviyo Quiet Hours is only half the job. To ensure everything works as expected—especially across time zones—you’ll need to run a few smart tests. 

Use Test Profiles Across Time Zones

• Create Klaviyo test profiles in different regions (e.g. US East Coast, UK, Australia).

• Assign unique time zones to each to see how quiet hours apply locally.

• This helps you avoid surprises with international flows.

Manually Trigger Test Flows

• Use manual triggers to simulate real SMS sends outside of quiet hours.

• Confirm that SMS messages are queued and sent after Quiet Hours by reviewing analytics.

• Pro tip: Trigger at 7:59 PM to test the boundary logic.

Check SMS Logs in Analytics

• Head to the Flow Analytics tab.

• Look for messages marked as “Waiting” or delayed.

• Review exact send times to confirm quiet hour enforcement.

Run Regional QA Simulations

• Before going live, simulate a real customer journey.

• Use test accounts in your top markets to confirm timing, tone, and delivery.

• Double-check against local quiet hours (especially if you override them).

If you're just starting with Klaviyo, Klaviyo Tutorial: 30-Minute Beginner's Guide can walk you through setting up flows, profiles, and testing features like Quiet Hours properly.

Best Practices for Using Klaviyo SMS Quiet Hours

Quiet Hours are powerful—but only when set up and managed correctly. Follow these proven strategies to avoid mistakes, stay compliant, and improve your SMS performance:

1. Enable Quiet Hours Globally
Set it once in Sender Preferences so it applies across all SMS flows by default. Start with 8 PM–11 AM local time unless your analytics suggest a better window.

2. Leave a Buffer After Quiet Hours End
Avoid sending messages at exactly 11:01 AM. Instead, allow a 15–30 minute delay to give users time to re-engage with their phones.

3. Don’t Overuse Overrides
Use the override toggle only for high-intent campaigns like flash sales. Segment wisely, avoid legally restricted regions, and always include opt-outs.

4. Use Localised Time Zones
Let Klaviyo detect customer time zones via area codes. For mixed-country flows, use conditional splits by country or region to prevent off-hour sends.

5. A/B Test Your Ideal Send Windows
Even with Quiet Hours, test when customers are most responsive post-morning, 11:30 AM, 2 PM? Use Klaviyo’s analytics to find your sweet spot.

6. Monitor “Waiting” Status in Flows
Track messages paused during quiet hours in Flow Analytics. Use this to troubleshoot delays or adjust timing based on engagement data.

7. Combine with Smart Sending
Let Quiet Hours handle sleep-time pauses and Smart Sending manage message frequency. This combo avoids spamming your list.

8. Simulate Regional Sends Before Launch
Test in multiple time zones to ensure proper message delay and delivery. 

9. Don’t Confuse Campaigns with Flows
Remember: Quiet Hours don’t apply to campaigns. Use manual scheduling or delays to control timing. Not sure how to structure your automation logic with these tips? Klaviyo Conditional Splits: Step-by-Step Guide will help you add logic based on region, segment, or behaviour.

10. Clean Up Tracking Parameters
Use lowercase UTMs to avoid split tracking in GA4. E.g. utm_campaign=spring_sale, not utm_campaign=Spring_Sale.

FAQs

1. Can I set different Quiet Hours for different flows?
No, the default Quiet Hours apply account-wide, but you can override them per message within each flow.

2. Will Quiet Hours apply to SMS sent via Klaviyo APIs or third-party integrations?
No—Quiet Hours only apply to messages sent through Klaviyo’s automated flow builder, not third-party-triggered sends.

3. Do Quiet Hours pause emails, too?
No—Quiet Hours are SMS-specific. For email timing control, use scheduling or Smart Sending separately.

4. Can I test Quiet Hours in Klaviyo’s preview mode?
Not fully. You’ll need to simulate live flows using test profiles in different time zones for accurate quiet hour behaviour.

5. Does enabling Quiet Hours affect delivery speed after the window ends?
No, once Quiet Hours end, Klaviyo sends the message immediately unless Smart Sending delays it further.

Conclusion

Your customers are busy—and often asleep—when many brands fire off their SMS campaigns. Klaviyo SMS Quiet Hours ensures you don’t become that brand. With just a few smart settings, you can protect your deliverability, reduce unsubscribes, and send texts at the right time. 

Whether you're running cart recovery, flash sales, or shipping alerts, timing matters more than ever. By using Quiet Hours wisely, you’re not only respecting your audience’s attention, you’re increasing your chance of making a sale. And if you’re unsure where to start, we can help.

Key Takeaways

• What It Is: Quiet Hours pause flow SMS sends during off-hours like 8 PM–11 AM.

• Why It Matters: Reduces unsubscribes and boosts click-throughs by avoiding bad timing.

• How It Works: Uses local time zones via area codes to queue SMS automatically.

• When to Override: Only for high-intent events, like flash sales, and not in restricted regions.

• Best Practices: Always test, stagger sends after 11 AM, and pair with Smart Sending for best results.

Struggling with late-night texts that annoy your customers?

We will assist you in configuring Klaviyo SMS Quiet Hours correctly, ensuring your messages arrive at the optimal time, enhancing engagement and maintaining compliance. Click here to receive a free audit with our experts today.