Average temperatures in Cayo Guillermo through the whole of September is 26. With the average high being 32 degrees and a low of 23 celsius. We have put some more information here:
| Month | Degrees Celsius |
|---|---|
| Temperature | 26 |
| High Temperature | 32 |
| Low Temperature | 23 |
| Sunshine Per Day | 8 |
Useful Links: Cayo Guillermo Weather: Average Weather & Yearly Climate