ShowSDRGuide
When is the best time to message conference attendees?
Weeks before the show, on a weekday, at any working hour, at a pace the app can carry. In 601 Whova messages the send hour made no difference (15% to 37%, no pattern); the two worst days were the two heaviest send days, and Sunday. In 351 iStack connection requests, late morning and midday Pacific sends were accepted about twice as often as evening sends, on a global audience, with other things changing at the same time.
Does the hour of day matter?
Whova, reply rate by send hour (Pacific): 07h 15% (8/55), 09h 28%, 11h 27% (12/44), 13h 26% (12/46), 14h 34% (18/53), 16h 30% (15/50), 17h 31%, 19h 31% (17/55), 20h 28% (13/46), 22h 37% (11/30). Evening Pacific is business hours in Denver and the East, and did as well as anything. Attendees read messages when they open the app, not when you send them.
iStack, acceptance by request hour (Pacific): first batch 10:00 to 14:00 accepted 23% (17/75) vs 17:00 to 20:00 7% (4/60); second batch 11:00 to 14:00 9% (9/103) vs 15:00 to 20:00 5% (5/111). A consistent two to one edge for midday, but the batches also differed by day, pace and wording. Treat it as a hypothesis worth testing on your own list.
Does the day matter?
Whova, reply rate by send day: Aug 13 (Wed) 37%, Aug 14 (Thu) 26%, Aug 15 (Fri) 23%, Aug 16 (Sun) 4% (1/24), Aug 17 (Mon) 28%, Aug 18 (Tue) 25%, Aug 24 (show day 2) 36%, Aug 25 (show day 3) 17%. Sunday was the outlier. Thursday and Friday were the two heaviest days (149 and 137 sends) and that, not the weekday, is why they underperformed: 97 of those messages silently failed to deliver.
Does the pace matter more than the clock?
Yes. On Whova, the days above 130 messages lost a fifth of them to silent failures, and failed messages replied at 6% against 30% for delivered ones. On iStack, 24 hour acceptance fell from 11% to 7% when the request pace tripled from 10 to 30 an hour. Spread the same volume over more days and the clock stops mattering.
How long before you can judge a send?
A week. Median time to an attendee's first reply on Whova was 2.9 days; 24% replied within a day and 48% after three days. Any test read at 24 hours will tell you the wrong thing.
What about time zones?
Conference audiences are global (the Affiliate World list spanned the Americas, Europe and Asia). Send inside the recipient's daytime where you can infer it from their company location, never at 3am local, and accept that the app's own notification timing does most of the work.
Questions
What time of day gets the most replies from conference attendees?
On Whova, no hour stood out across 601 messages; rates ran 15% to 37% with no pattern. On iStack, midday Pacific requests were accepted about twice as often as evening ones in both batches.
Should I avoid weekends?
Sunday replied at 4% (1 of 24) in our data, against 23% to 37% on weekdays. One Sunday is thin evidence, but there is no reason to spend sends on it.
How many messages a day is too many?
On Whova, silent failures appeared above roughly 130 messages a day from one account. Keep a human pace and verify every send inside the thread.
How long should I wait before following up?
At least three to five days. Half of the attendees who replied did so after three days.
Source: ShowSDR campaign ledgers, Contact.io 2026 (Whova, Denver, August 23 to 25) and Affiliate World Americas 2026 (iStack, Cancún, September 7 to 8), reconciled against the apps' own thread history after each campaign. Full tables and method: Conference outreach benchmarks 2026. Last reviewed 20 September 2026.