Generally, you can anticipate the weather in San Francisco in the month of September is 12 with a high of 21 with lows of 13 degrees celsius. We have put some more detail below here:
| Month | Degrees Celsius |
|---|---|
| Temperature | 12 |
| High Temperature | 21 |
| Low Temperature | 13 |
| Sunshine Per Day | 9 |
Useful Links: San Francisco Weather: Average Weather & Yearly Climate