Do story points include weekends?

If you're asking whether points include weekends, you're already estimating in days.

Story points are relative effort, not duration. A 5 isn't 40 hours; it's "this is bigger than the reference story." Whether the team works weekends, takes Fridays off, or runs four-day weeks doesn't enter the estimate, because the estimate isn't a measure of calendar time.

Where weekends do matter is in velocity. Velocity is points-per-sprint, and sprint length is calendar time. A team with a public holiday in the middle of a sprint will have a lower velocity that sprint, because they had fewer working hours to spend the same effort on. That's the right place for weekends to show up — in the calendar layer, not the points layer.

Points don't have weekends. Velocity does.

See story points vs hours for the broader version of this trap; how many points per sprint for the velocity story.