Usually the average weather in San Juan all through December is 24. Throughout the month you should see a high of 28 and average daily low being 22. Our table below has the full details:
| Month | Degrees Celsius |
|---|---|
| Temperature | 24 |
| High Temperature | 28 |
| Low Temperature | 22 |
| Sunshine Per Day | 9 |
Useful Links: San Juan Weather: Average Weather & Yearly Climate