1 in 5 PRs merge on Monday. Friday deployments? Not as common as you think.
Monday Merges
658,296 PRs
Based on 3,387,250 merged PRs | GitHub Archive / BigQuery | December 2024
When does code actually ship? Our analysis of 3,387,250 merged PRs reveals a clear pattern: Monday dominates, Friday surprises, and weekends are busier than you'd expect.
| Day | PRs Merged | % of Total |
|---|---|---|
| Monday | 658,296 | 19.08% |
| Tuesday | 622,722 | 18.05% |
| Wednesday | 500,485 | 14.51% |
| Thursday | 480,401 | 13.93% |
| Friday | 481,768 | 13.97% |
| Saturday | 317,648 | 9.21% |
| Sunday | 388,062 | 11.25% |
Monday isn't just another day—it's when nearly 1 in 5 PRs get merged. That's 658,296 pull requests in our dataset, more than any other day of the week.
Why? The pattern suggests a clear workflow: PRs get opened throughout the week, reviews pile up, and then everything clears out Monday morning.
Engineers clear their review queues first thing Monday. That Friday PR? It finally gets approved.
CI/CD pipelines run over the weekend. By Monday, automated checks have completed and PRs are ready to merge.
"Monday isn't just the start of the work week—it's when 1 in 5 PRs finally get merged."
"Don't deploy on Friday" is practically an engineering proverb. But how much code actually ships on Friday?
Only 481,768 PRs merged on Fridays—less than Tuesday, Wednesday, or Thursday.
Friday actually has the lowest merge rate of any weekday. Engineers either finish their work earlier in the week, or they consciously avoid shipping before the weekend.
"Friday deployments? Only 14% of code ships then."
Here's the surprise: weekends aren't as quiet as you'd think. Combined, Saturday and Sunday account for 20.5% of all merges—roughly 705,710 PRs in our dataset.
11.25%
388,062 PRs merged
9.21%
317,648 PRs merged
Interestingly, Sunday sees more merges than Saturday. This could be engineers preparing for Monday, automated processes running on a schedule, or global teams where Sunday is a workday.
The Monday spike tells us something important: reviews queue up over the weekend and get cleared Monday morning.
If your team struggles with review latency, look at your Friday afternoon habits. Are PRs sitting in review queues over the weekend? Consider setting a "merge by Thursday" goal for work-in-progress PRs, or schedule dedicated review time early in the week.
If reviews pile up by Friday, they'll sit until Monday. Consider a Thursday review push to keep PRs moving.
Monday sees the highest merge volume. Ensure your CI/CD can handle the surge, and have on-call engineers ready for issues.
20% of merges happen on weekends. If that's coming from your team, it might signal workload issues—or just timezone differences.
Friday has the lowest weekday merge rate. Whether by policy or instinct, engineers are already avoiding Friday deployments.
This analysis is based on 3,387,250 merged pull requests from GitHub Archive / BigQuery during December 2024. Merge day is determined by the UTC timestamp of the merge event. For full methodology, see the complete study.
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