Last updated: August 27, 2025
In May, the average temperature in San Juan, Mexico is a warm 28°C (83°F), with extremes ranging from a refreshing 15°C (59°F) to a sizzling 44°C (111°F). Expect 86 mm (3.4 in) of precipitation spread over 8 days, contributing to an average humidity of 82%. Whether you're soaking up the sun or enjoying a light drizzle, the climate is sure to make your visit memorable!
In May in San Juan, the average temperature is 28°C (83°F). Maximums can reach 44°C (111°F), while minimums can drop as low as 15°C (59°F). Travelers should be prepared for warm days and cooler evenings during this time.
In San Juan in May, the precipitation amount reaches 86 mm (3.4 in) over the course of 8 days.
In San Juan in May, humidity is 82%. With an average temperature of 28°C (83°F), this humidity feels like stepping into a warm, damp embrace, which can make traveling feel heavy and exhausting, as every movement can be met with a sticky veil of moisture that clings to the skin.
In San Juan in May, the maximum UV index is 12, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, underscoring the importance of sun protection. For detailed information, you can check the Hourly UV Index in San Juan.
UV Risk Categories
Weather in San Juan varies notably across the year, with each month offering distinct climate conditions. This page compares May’s weather to other months in San Juan, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 16°C (61°F) | 20 mm (0.8 inches) | 84% | high |
| February Weather | 18°C (65°F) | 13 mm (0.5 inches) | 83% | very high |
| March Weather | 23°C (73°F) | 25 mm (1.0 inches) | 78% | very high |
| April Weather | 25°C (78°F) | 46 mm (1.8 inches) | 81% | extreme |
| May Weather | 28°C (83°F) | 86 mm (3.4 inches) | 82% | extreme |
| June Weather | 30°C (86°F) | 86 mm (3.4 inches) | 74% | extreme |
| July Weather | 31°C (87°F) | 78 mm (3.1 inches) | 68% | extreme |
| August Weather | 31°C (89°F) | 16 mm (0.6 inches) | 67% | extreme |
| September Weather | 28°C (83°F) | 119 mm (4.7 inches) | 75% | extreme |
| October Weather | 24°C (76°F) | 56 mm (2.2 inches) | 78% | very high |
| November Weather | 20°C (68°F) | 23 mm (0.9 inches) | 83% | high |
| December Weather | 17°C (64°F) | 20 mm (0.8 inches) | 86% | high |