Campaign Scheduling and Timezone Optimization in AcelleMail

The scheduling decision#

When you launch a campaign, you pick one of:

AcelleMail's scheduler defaults to the account-wide timezone. Subscriber-local timezones require per-subscriber timezone tagging.

The scheduling UI#

Step 1: Open the schedule step#

In the campaign builder, after completing setup + template, you reach the Schedule step:

By default, "Send now" is selected. Toggle to "Schedule for later" to set a specific date+time.

Step 2: Pick the schedule time#

Pick the date + time. The picker uses your account timezone (visible in the field label).

Step 3: Confirm the timezone#

Settings → Account → Timezone:

This is what AcelleMail uses for all schedule calculations + display. Change it once when your account is created; rarely after.

Best practices for send time#

Default rule: weekday mid-morning, recipient timezone#

For most B2C and B2B audiences, the consistent winner is:

• Weekday: Tuesday / Wednesday / Thursday (avoid Monday + Friday)
• Time: 9:30am - 11:00am in recipient's timezone
• Avoid: weekends, early morning (<7am), late afternoon (>4pm), midnight

For a US-East-Coast-dominant audience using account timezone of America/New_York:

Tuesday 09:30 ET
Tuesday 10:00 ET
Wednesday 10:00 ET
Thursday 09:30 ET

These windows hit recipients when they're starting their work day — open rates peak.

When to break the rule#

Multi-timezone audience#

If your audience is split US + EU + APAC, three patterns:

Pattern A: Send at "your" timezone (simplest)#

Tuesday 10:00 ET
  → US East gets it at 10am local
  → US West gets it at 7am local (early)
  → London gets it at 3pm local (afternoon — different but workable)
  → Tokyo gets it at 11pm local (night — engagement drops)

Sub-optimal for non-US recipients but easy to ship.

Pattern B: Multiple send waves#

Tuesday 09:30 PT  (West Coast US)
Tuesday 09:30 ET  (East Coast US)
Tuesday 09:30 GMT (London)
Tuesday 09:30 JST (Tokyo)

Each subscriber's timezone tag determines which wave they receive in. AcelleMail handles this via per-segment campaign launches OR via per-subscriber send-time-optimization (advanced).

Pattern C: Subscriber-local timezone#

If your install supports per-subscriber timezone:

Tuesday 09:30 in subscriber's local timezone

Each subscriber receives at 9:30am THEIR time. AcelleMail's scheduler does the math.

Requires:

• Per-subscriber timezone field on the list
• Send-time optimization feature enabled (varies per install)

Common UI signals + fixes#

Send-time optimization#

AcelleMail's send-time optimization (varies per install) uses each subscriber's past-open-time pattern to predict the best send time for them:

Subscriber A: opens at 9:30am ET routinely → schedule for 9:30am ET
Subscriber B: opens at 6:30pm PT (evening browse) → schedule for 6:30pm PT
Subscriber C: no clear pattern → use default 10:00 account TZ

If your install has this feature, enable in Settings → Sending → Send-time optimization.

How to pick the right time when you don't know your audience#

1. Test 3 windows over 6 weeks (Tuesday 10am, Wednesday 2pm, Sunday 9am)
2. Compare open rates across the 3 cohorts
3. Continue with the winner
4. Re-test annually as audience behavior shifts

Engaged segment (open <7d ago):  Tuesday 9:30 ET (proven optimal)
At-risk segment (open >30d ago): Saturday 10am ET (different cadence)
New segment (signup <14d ago):   Welcome series — automation-triggered

#!/bin/bash
# Daily-run script: identify optimal time per segment based on last 90 days
ACELLE_TOKEN="..."
LIST_UID="..."

for segment in engaged at-risk new; do
  # Query open events for this segment over last 90 days, group by hour-of-week
  best_time=$(curl -sH "Authorization: Bearer $ACELLE_TOKEN" \
    "https://acellemail.com/api/v1/lists/$LIST_UID/opens-by-hour?segment=$segment&days=90" \
    | jq -r '.peak_hour')

  echo "Segment $segment: peak engagement at $best_time"
  # Set campaign schedule via API or store for next manual launch
done

# Get subscriber timezones from your data + bucket per region
sub_tzs=$(curl -sH "Authorization: Bearer $TOKEN" \
  "https://acellemail.com/api/v1/lists/$LIST_UID/subscribers/timezones" | jq -r '.')

# Schedule per-bucket campaigns
for tz in $sub_tzs; do
  schedule_time=$(calculate_optimal_time $tz 'Tuesday' '09:30')
  schedule_campaign $LIST_UID $tz $schedule_time
done

Related articles#

• Your first email campaign in AcelleMail
• Email subject line formulas that work
• A/B testing email subject lines
• Birthday and anniversary email automations