Email sits in an inbox until someone chooses to look. WhatsApp buzzes a phone in a pocket. That single difference reverses much of the received wisdom about send timing.
The read window is short
Most WhatsApp messages that get read are read quickly — typically within minutes rather than hours. There is very little long tail. That means the time you send is close to the time you are read, so you are not optimising for when someone next checks a mailbox; you are choosing when to interrupt them.
Think about the interruption, not the open rate
The right question is not "when will they read it" — they will read it almost immediately — but "when is an interruption from us welcome, and when can they act on it?" A promotion read at 11pm gets seen and forgotten because nothing can be done about it.
The two windows that generally work
Late morning, once the day has settled but before lunch. And early evening, after commute and before the household evening. Both are times when people have a free hand and can act on what they read.
Times to avoid
- Before 9am and after 9pm. Some jurisdictions restrict commercial messaging hours outright; beyond legality, it generates blocks.
- Monday morning for anything non-urgent, competing with the week's backlog.
- Friday evening unless someone is available to reply.
- During a major event — a cricket final, an election result — where you will be ignored or resented.
Time zones and staggering
If your list spans regions, send by region rather than all at once. A single send at 10am IST is 5:30am in London. This is elementary and routinely forgotten, and it is the most common cause of an unexplained block spike in a subset of a list.
Staggering also has an operational benefit: it spreads the reply load rather than delivering it all in one ten-minute burst your team cannot absorb.
Match timing to message type
- Utility messages — send when the event happens. Nobody wants a delayed shipping notification because it was outside a window.
- Reminders — far enough ahead to act on. An appointment reminder an hour before is useless if travel takes ninety minutes.
- Promotions — when the customer can actually buy, which for many businesses means evenings and weekends rather than mid-morning.
- Time-limited offers — early enough that the deadline is genuinely reachable.
Test on your own audience
General patterns are a starting point, not an answer. Split a campaign across two send times a few times and compare reply rate rather than read rate — reads are near-universal and therefore uninformative. Four or five such tests will tell you more about your audience than any published benchmark.
And once you find a window that works, keep using it. Predictability is itself valuable: people learn when to expect you, and expected messages get blocked far less often.