Short answer
Parties posted mostly in working hours, but posts made in the evening and on Sundays drew more engagement. The differences are modest.
What the evidence shows
- Across 856,696 posts from 112 party pages and 74 leaders' pages in 20 countries, two thirds appeared between 09:00 and 18:00, fewer than one in ten after 21:00 and fewer than one in five at weekends.
- Comparing posts by the same page in the same month, posts made between 21:00 and midnight drew about 10% more interactions than posts made at midday, and posts from 18:00 to 21:00 about 4% more.
- Sunday posts drew about 9% more than Monday posts.
- Posts made in an hour when other parties in the country were also posting drew more, not less.
Caveats
The differences are modest, and they say nothing about what posts said.