Normally, you can expect the weather in Karlsruhe in the course of September is 15. Average highs are typically 21 with low average temperatures being 12 celsius. The table below includes more detail:
| Month | Degrees Celsius |
|---|---|
| Temperature | 15 |
| High Temperature | 21 |
| Low Temperature | 12 |
Useful Links: Karlsruhe Weather: Average Weather & Yearly Climate