San Juan weather in October

Averages from 2021–2025 (155 days of record).

Average high

87°F

Average low

77°F

Rainy days

~19 per month

Total precipitation

5.0 in

Warmest recorded

93°F

Coldest recorded

72°F

Expect October days in San Juan to top out around 87°F and cool to about 77°F overnight, with roughly 19 days of measurable rain across the month. In recent years October has ranged from 72°F to 93°F.