What does 'seasonally adjusted' mean? Why did German unemployment fall in September but the adjusted figure rise?

Germany's Federal Employment Agency reported that registered unemployment fell by 67,000 to 2,994,000 in September. In the same report, it said that seasonally adjusted unemployment rose by 12,000 (full report). Both are true, and the difference is exactly what seasonal adjustment is for.

Many economic figures follow a calendar pattern. Unemployment in Germany usually falls in the autumn, as people return to work after the summer break and training starts. A fall of 67,000 sounds good, but it is the kind of fall the autumn normally brings. In September 2026 it was smaller than usual, so after the usual seasonal pattern is removed, what remains is a rise of 12,000.

Seasonal adjustment estimates the normal calendar effect from past years and takes it out, so you can compare one month with the next. It is an estimate, so it can be revised, and different agencies use different methods.

Please explain it as simply as you can:

• How would you explain seasonal adjustment to a friend, perhaps with an example like ice cream sales in summer or retail sales in December?
• Which data do you look at before adjustment and which after, and why?
• Has a seasonally adjusted number ever confused you, or changed a trade?
• Which releases do you find most affected by the season?

How to read an economic calendar explains how to read the numbers in a release.

Please keep replies friendly and practical. Posts that promise a direction or sell signals will be removed.