Last updated: August 27, 2025
In September, San Martin, Peru, enjoys a delightful climate characterized by a pleasant average temperature of 21°C (69°F), with daytime maximums reaching up to 29°C (85°F) and cooler nighttime lows around 16°C (60°F). This period sees minimal precipitation, with a total of just 3 mm (0.1 in) and zero rainy days, making it an ideal time for outdoor activities. Coupled with a humidity level of 75%, the month provides a comfortable atmosphere for visitors wishing to explore the region's natural beauty without the worry of wet weather.
In September, San Martin, Peru, begins to transition into slightly warmer weather, characterized by mild temperatures that offer a comfortable escape for visitors. The average temperature hovers around 21°C (69°F), with nighttime lows dropping to 16°C (60°F) and daytime highs reaching up to 29°C (85°F). This month serves as a pleasant bridge between the cooler months of July and August and the warmer October, showcasing a gradual increase in warmth that aligns with the onset of spring in the Southern Hemisphere. The trend reflects a diverse climate, inviting exploration of San Martin's lush landscapes and vibrant culture as it basks in the gentle sunshine of early spring.
In September, San Martin, Peru, experiences remarkably low precipitation, with only 3 mm (0.1 in) of rain recorded, which falls over no rainy days this month. This trend is part of a larger seasonal pattern, as rainfall begins to dwindle after the wetter months of March and February, where averages soar to 157 mm (6.2 in) and 65 mm (2.5 in), respectively. Following August's virtually non-existent rainfall, September continues the dry spell, leading into a gradual increase again in October. With this lapse in precipitation, the landscape remains relatively parched, setting the stage for the drier conditions typical of the post-rainy season in San Martin.
September marks a notable shift in humidity levels in San Martin, Peru, where the average humidity hovers around 75%. After experiencing a gradual decline from the peak of 89% in January through the drier months of July and August (both at 71%), September signals a mild rise, suggesting a transition back towards more moisture-laden air as the region heads into the rainier season. This subtle increase reflects the typical rhythm of the climate, where humidity levels generally fluctuate, peaking in the earlier months and gradually stabilizing toward the end of the year, with December reaching 86% once again. As the humidity rises slightly in September, residents and visitors alike can expect a return to the lush, vibrant atmosphere characteristic of San Martin's tropical environment.
In September, San Martin, Peru, continues to experience an extreme UV Index, registering at 14, identical to the levels seen in both October and November. This consistency in the UV Index suggests that sun safety remains a crucial priority, as even limited exposure can result in skin damage in just 10 minutes. The trend of high UV Index values throughout the year underscores the necessity for residents and visitors alike to take protective measures seriously, especially as the weather remains warm and sunny. For more detailed insights on UV exposure in the region, check out the information available at San Martin UV Index.
UV Risk Categories
September in San Martin, Peru, offers a delightful blend of warmth and sunshine, as the region enjoys a remarkable 319 hours of bright sunlight. This month subtly bridges the end of winter and the onset of spring, showcasing a slight dip from August's peak of 330 hours yet still maintaining a robust offering of daylight. As the landscape begins to bloom, the overall trend of increasing sunshine hours from the start of the year culminates in the vibrant atmosphere of September, which is only slightly overshadowed by the sun-drenched month of May, when the city basked in an impressive 329 hours. With consistent sunshine continuing into the fall, September stands out as a month of transition, promising both pleasant weather and stunning natural beauty.
In September, San Martin, Peru, enjoys a moderate 52% chance of sunny weather, marking a peak in the transition from the cooler months to warmer days. This month stands out as a significant improvement compared to the lower probabilities in the early part of the year—such as 25% in March and 30% in November. Following a streak of brighter conditions in May and July, September sets the tone for the approaching warmth of the latter months, encouraging outdoor activities and vibrant local festivities. As the region shakes off its winter chill, visitors can expect a blend of sunshine and mild temperatures, making this an appealing time to experience the beauty of San Martin.
In San Martin, Peru, September marks a delightful transition back to 12 hours of daylight, mirroring the consistent patterns seen in the earlier months of the year. From January to March, the days are comfortably long, providing ample sunlight for outdoor activities and fostering a vibrant atmosphere. As the year progresses into April through August, daylight dips to 11 hours, suggesting a slight shift in rhythm as the region transitions through cooler months. However, just as the seasons begin to change, September brightens again, returning to the equilibrium of 12 hours. This cyclical nature of daylight not only highlights the region's unique geographical position but also invites locals and visitors alike to revel in the beauty of Peru's diverse landscapes under a robust sun.
As September arrives in San Martin, Peru, the winds pick up slightly, averaging 3.7 m/s (8 mph)—the same speed noted in August, hinting at a consistent meteorological pattern. Following a gradual increase throughout the spring and summer months, the wind remains steady as the region transitions into the fall season. Interestingly, the average wind speed in this period aligns with the peak gusts seen in July and August, suggesting a stable, refreshing breeze that characterizes the transition into the vibrant landscape of September. This seamless flow into autumn encourages outdoor exploration, with the winds lending a lively energy to the region's stunning natural beauty.
Weather in San Martin varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in San Martin, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January in San Martin showcase contrasting weather patterns. In September, temperatures range from a mild 16°C (60°F) at night to a warm 29°C (85°F) during the day, with an average of 21°C (69°F). The month experiences very little precipitation, averaging only 3 mm (0.1 in) without any rainy days, and humidity is a comfortable 75%. In contrast, January brings hotter temperatures, with nighttime lows of 19°C (67°F) and daytime highs soaring to 35°C (94°F), resulting in an average of 26°C (78°F). This month sees a significant increase in rainfall, totaling about 20 mm (0.8 in) over four days, along with higher humidity levels at 89%. For a closer look at January weather specifics, you can refer to San Martin weather in January.
September and February present distinctly different weather patterns. In September, temperatures range from a mild 16°C (60°F) at night to a warm 29°C (85°F) during the day, with minimal precipitation of only 3 mm (0.1 in) over the entire month and a humidity level of 75%. In contrast, February sees higher temperatures, with nighttime lows of 20°C (68°F) and daytime highs soaring to 35°C (96°F). This month experiences significantly more rainfall, totaling 65 mm (2.5 in) across approximately 9 days, accompanied by increased humidity at 87%. Overall, February is hotter and wetter than September. For more detailed information about February weather, visit San Martin weather in February.
September and March present quite contrasting weather conditions. In September, temperatures are milder, with a minimum of 16°C (60°F) and an average of 21°C (69°F), reaching a maximum of 29°C (85°F). This month experiences minimal precipitation, averaging only 3 mm, and is characterized by a comfortable humidity level of 75%. In stark contrast, March boasts higher temperatures, with a minimum of 21°C (69°F), an average of 27°C (80°F), and maximum highs soaring to 36°C (96°F). Additionally, March is significantly wetter, receiving about 157 mm of rain over 9 days, combined with higher humidity at 87%. For a deeper dive into the specifics of March weather, visit San Martin weather in March.
September and April present distinctly different weather patterns. September typically boasts milder temperatures, with a minimum of 16°C (60°F) and an average of 21°C (69°F), while April heats up significantly, featuring a minimum of 18°C (65°F) and an average of 25°C (78°F). In September, rainfall is almost nonexistent with only 3 mm (0.1 in) and no days of precipitation, creating a drier atmosphere with 75% humidity. In contrast, April is wetter, receiving 33 mm (1.3 in) of rain across five days, accompanied by higher humidity at 86%. This makes April feel warmer and more humid overall. For a more detailed look at April's weather, you can refer to San Martin weather in April.
September and May present contrasting weather patterns. In September, temperatures range from a mild 16°C (60°F) to a maximum of 29°C (85°F), with low humidity at 75% and almost no precipitation, making it a dry month. In contrast, May tends to be warmer, with minimum temperatures also starting at 16°C (62°F), but reaching up to 33°C (91°F) on the hotter days. This month experiences more humidity at 89% and sees about 13 mm (0.5 in) of rainfall over four days. For more information on May weather specifically, visit San Martin weather in May.
September weather features milder temperatures compared to June, with average highs reaching 29°C (85°F) and lows around 16°C (60°F). In contrast, June tends to be slightly warmer, with average high temperatures of 31°C (88°F) and a minimum of 17°C (63°F). Both months experience relatively low precipitation, but September is notably drier with no recorded rainy days, whereas June has about 6 mm of rain spread over two days. Humidity levels are also lower in September at 75%, compared to June’s higher humidity of 84%. For a detailed look at June's weather, you can visit San Martin weather in June.
In comparing the weather of September and July, we see some intriguing similarities and slight variations. Both months experience a comfortable average temperature of around 21°C (69°F), but September tends to have slightly warmer daytime highs, reaching up to 29°C (85°F) compared to July's maximum of 28°C (82°F). Additionally, September boasts very little precipitation with only 3 mm over 0 days, while July has a bit more rainfall, totaling 4 mm over the course of 1 day. Humidity levels are relatively comparable, with September at 75% and July at 71%. For a closer look at July weather specifics, visit San Martin weather in July.
In September, the weather remains quite pleasant with temperatures ranging from a minimum of 16°C (60°F) to a maximum of 29°C (85°F) and an average of 21°C (69°F). This marks a slight increase in warmth compared to August, which experiences a minimum of 15°C (59°F) and a maximum of 28°C (83°F), with an average temperature also at 20°C (69°F). Both months see minimal precipitation, with September recording just 3 mm (0.1 in) and no rainy days, similar to August's 2 mm (0.1 in) and also no days of rainfall. Notably, September has a slightly higher humidity level at 75% compared to August's 71%. For a detailed look at August's conditions, visit San Martin weather in August.
September typically enjoys warm weather with temperatures ranging from a minimum of 16°C (60°F) to a maximum of 29°C (85°F) and an average of 21°C (69°F). The month is characterized by very low precipitation, averaging just 3 mm (0.1 in) and experiencing no rainy days, along with relatively high humidity at 75%.
In contrast, October sees a slight increase in temperatures, with the maximum reaching 30°C (86°F) while maintaining a minimum of 16°C (61°F) and an average of 21°C (70°F). However, October is more humid at 77% and experiences some rainfall, totaling about 10 mm (0.4 in) across two days. For a detailed overview of October weather specifics, you can check San Martin weather in October.
In September, the weather tends to be warm and relatively dry, with temperatures ranging from a minimum of 16°C (60°F) to a maximum of 29°C (85°F) and an average of 21°C (69°F). The month boasts a low precipitation level of just 3 mm (0.1 in) over 0 rainy days, along with a humidity level of 75%. In contrast, November experiences slightly cooler nights with a minimum temperature of 14°C (58°F), but warmer daytime highs, reaching up to 31°C (88°F) and averaging at 22°C (71°F). November is also wetter, with 14 mm (0.6 in) of rainfall spread over 3 days and a marginally higher humidity of 79%. This shift indicates a transition towards a more humid and rainy pattern as the year progresses. For more details, check out San Martin weather in November.
In September, the weather features a comfortable range with minimum temperatures around 16°C (60°F) and an average of 21°C (69°F), peaking at a maximum of 29°C (85°F). This month is relatively dry, with only 3 mm of precipitation over zero rainy days and humidity levels at 75%. In contrast, December sees slightly warmer temperatures, with a minimum of 17°C (63°F) and an average of 24°C (75°F), climbing to a maximum of 32°C (91°F). However, December also brings an increase in rainfall, totaling 29 mm over seven rainy days, along with higher humidity at 86%. For more detailed information on December weather, check out San Martin weather in December.
As September arrives in San Martin, you can expect pleasantly warm days with average temperatures around 21°C (69°F), offering a delightful reprieve from the more intense heat of the summer months. This period sees a notable decrease in precipitation, with no rainy days recorded, allowing for plenty of sunshine and outdoor activities. The humidity remains a constant companion at 75%, but the lack of rainfall creates a comfortable atmosphere. Overall, September stands out as a month of transition, making it an ideal time to explore the beauty of San Martin. For more detailed climate insights, check out San Martin Climate.