Last updated: August 27, 2025
In September, the average temperature in San Marcos, Peru is a pleasant 12°C (54°F), but be prepared for a range: it can dip to a chilly 5°C (40°F) or rise to a warm 23°C (73°F). Expect 77 mm (3.0 in) of precipitation spread over 12 days, accompanied by an average humidity level of 42%. Whether you're exploring the sights or enjoying local cuisine, pack accordingly for this mild yet variable climate!
In September in San Marcos, the average temperature is 12°C (54°F). Maximums can reach 23°C (73°F), and minimums can be as low as 5°C (40°F). This mild climate makes it an ideal time for travelers to explore and enjoy the local attractions comfortably.
In San Marcos in September, the precipitation amount is 77 mm (3.0 in) spread over 12 days.
In San Marcos in September, humidity is 42%. With an average temperature of 12°C (54°F), this humidity feels like a crisp, refreshing environment that encourages outdoor exploration, making it perfect for sightseeing and leisurely strolls without the discomfort of excessive heat.
In San Marcos in September, the maximum UV index reaches an alarming 17, which falls under the extreme Exposure Category. With a time to burn of just 10 minutes, it's crucial to stay protected. For more details on the hourly UV index in San Marcos, you can check Hourly UV Index in San Marcos.
UV Risk Categories
Weather in San Marcos varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in San Marcos, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 12°C (55°F) | 192 mm (7.5 inches) | 83% | extreme |
| February Weather | 13°C (55°F) | 245 mm (9.6 inches) | 81% | extreme |
| March Weather | 12°C (54°F) | 335 mm (13.2 inches) | 88% | extreme |
| April Weather | 12°C (54°F) | 185 mm (7.3 inches) | 85% | extreme |
| May Weather | 12°C (54°F) | 103 mm (4.0 inches) | 78% | extreme |
| June Weather | 12°C (54°F) | 48 mm (1.9 inches) | 62% | extreme |
| July Weather | 12°C (53°F) | 28 mm (1.1 inches) | 44% | extreme |
| August Weather | 12°C (54°F) | 42 mm (1.7 inches) | 38% | extreme |
| September Weather | 12°C (54°F) | 77 mm (3.0 inches) | 42% | extreme |
| October Weather | 12°C (54°F) | 194 mm (7.6 inches) | 58% | extreme |
| November Weather | 13°C (55°F) | 219 mm (8.6 inches) | 69% | extreme |
| December Weather | 13°C (55°F) | 259 mm (10.2 inches) | 82% | extreme |