Last updated: August 31, 2025
In Ilam, Nepal, September ushers in a characteristically humid climate, with temperatures ranging from a maximum of 29°C (85°F) to a comforting average of 21°C (71°F), and dipping down to a minimum of 16°C (62°F). This month is defined by significant rainfall, accumulating to 375 mm (14.8 in) over 28 days, contributing to the lush, green landscape that Ilam is renowned for. With humidity levels soaring to 93%, the air is thick and revitalizing, making September an ideal time to experience the region's vibrant scenery and rich natural beauty.
In September, Ilam, Nepal experiences a gentle transition as the summer heat begins to wane. The temperatures range from a mild 16°C (62°F) at night to a comfortable 29°C (85°F) during the day, with an average of 21°C (71°F), marking a slight drop from the sweltering peaks of summer. This month often sees a respite from the intense monsoon rains, allowing lush greenery to thrive while offering a pleasant climate for outdoor activities. As days become shorter and cooler, visitors can enjoy the stunning landscapes that Ilam has to offer, all while being embraced by the crisp, refreshing air that heralds the arrival of autumn.
In September, Ilam, Nepal experiences a significant drop in precipitation compared to the summer months, receiving 375 mm (14.8 in) of rain over approximately 28 days. Although this marks a decrease from the torrential rains of July and August, it still contributes to a notably wet season, with rainfall patterns reflecting the monsoon's gradual retreat. The rainfall in September is about 90 mm less than in August and contrasts sharply with the lighter, more moderate totals in the following months. This transition from intense summer storms to the drier autumn months highlights the region's shifting climate, as it prepares for the impending cooler and less wet October, which typically sees a further reduction in precipitation.
In September, Ilam, Nepal, continues to experience high humidity, maintaining a notable 93% level that has persisted since July and August. This peak humidity reflects the region's monsoon season, where heavy rainfall contributes to the oppressive moisture in the air. The transition from summer to autumn marks a gradual decline in humidity levels, yet September's figures remain consistent with the previous months, showcasing a lingering dampness before the onset of drier conditions in October. This trend highlights Ilam's unique climatic patterns, where the wet season significantly influences atmospheric moisture, creating a rich, vibrant environment even as the year moves toward its gradual cool-down.
As September rolls in, Ilam, Nepal, continues to experience an extreme UV Index of 12, maintaining the heightened sun exposure seen in the preceding months. With a short burn time of just 10 minutes, it's vital for residents and visitors alike to remain vigilant about sun protection. This trend underscores a pattern of rising UV levels from January's UV Index of 6 to this month's peak, demonstrating a significant increase in solar intensity as the year progresses. As October approaches, the UV Index is expected to decrease to 10, yet remains in the very high exposure category, reminding us that sun safety is paramount year-round. For more insights into UV radiation in this beautiful region, visit the Ilam UV Index.
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As summer gently transitions into autumn, September brings a delightful blend of warmth and sunlight to Ilam, Nepal. With 261 hours of sunshine, this month stands out as a refreshing respite, especially following the lush greenery of the preceding summer months. The sunshine hours, while slightly lower than the peak of 337 hours in May, still reflect a vibrant landscape bathed in golden light. Unlike the previous months of July and August, which saw a dip in sunshine, September marks a slight rebound, hinting at a comfortable closeness to the sunny promise of October. This gradual shift not only enhances the vistas of rolling tea gardens but also foreshadows the brilliant hues of autumn foliage, inviting both locals and travelers to revel in the enchanting charm of this picturesque location.
In Ilam, Nepal, September marks a transitional phase as the weather shifts from the heavy monsoon season, offering a modest 23% chance of sunny days. This figure reflects a gradual recovery from the almost non-existent sunshine in the preceding months of July and August, which see only 4% and 3% chances of clear skies, respectively. While the likelihood of sun in September is still low compared to the earlier months of the year, it shows a noteworthy improvement over the summer's persistent rains. As the region moves into October, the chances of sunshine rise significantly to 48%, suggesting that the sunny days are just around the corner. This pattern highlights the variability of Ilam's climate, where early autumn begins to break through the monsoon gloom.
September in Ilam, Nepal, enjoys a delightful 12 hours of daylight, marking a transition as the days start to shorten from the summer peak. Following a vibrant summer of consistent 13 hours of sunlight from May through August, the slight dip in daylight reminds us that autumn is on the horizon. This gradual decrease continues into October, when daylight dwindles to 11 hours. As the year progresses, the pattern shifts from the ample sunshine of summer months to the softer, shorter days of winter, creating a beautiful rhythm that reflects the changing seasons of this enchanting region.
In September, the winds in Ilam, Nepal, continue their gentle decline, reaching an average speed of 1.0 m/s (2 mph). This marks the tail end of a summer season characterized by relatively calm breezes, as the region transitions into the cooler months. Throughout the year, wind patterns exhibited a thoughtful ebb and flow, starting from a brisk 1.4 m/s in April before gradually tapering off. Notably, September's winds mirror those of both July and August, suggesting a consistent tranquility that envelops the region during this time. As autumn approaches, the subtle shifts in wind speed hint at the changing seasons, while still inviting residents and visitors alike to enjoy the serene landscapes of Ilam amidst a soothing backdrop of soft breezes.
Weather in Ilam varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Ilam, focusing on differences in temperature, rainfall, humidity, and UV levels.
In September, temperatures range from a mild 16°C (62°F) at night to a warm 29°C (85°F) during the day, averaging around 21°C (71°F). This month is characterized by high humidity at 93% and significant rainfall, with 375 mm (14.8 in) of precipitation spread over 28 days. In stark contrast, January experiences much cooler weather, with minimum temperatures dipping to 0°C (33°F) and a moderate daily high of 22°C (71°F), averaging only 9°C (49°F). Additionally, January sees a drastic reduction in precipitation, totaling just 27 mm (1.1 in) over 7 days, accompanied by a lower humidity level of 59%. For a closer look at January weather specifics, visit Ilam weather in January.
In September, the weather is notably warmer, with average temperatures ranging from a minimum of 16°C (62°F) to a maximum of 29°C (85°F). The month experiences high humidity at 93% and substantial rainfall, accumulating 375 mm (14.8 in) over 28 days. In contrast, February presents a much cooler climate, with average temperatures from a minimum of -1°C (31°F) to a maximum of 22°C (73°F). Precipitation decreases significantly to 64 mm (2.5 in) over just 13 days, and humidity drops to 61%. For those considering travel, more detailed information can be found on Ilam weather in February.
September and March present quite contrasting weather patterns. In September, temperatures range from a cool 16°C (62°F) at night to a warm 29°C (85°F) during the day, with an average of 21°C (71°F). This month is characterized by high humidity at 93% and significant rainfall, totaling 375 mm (14.8 inches) over 28 days. In contrast, March experiences a much cooler climate with night temperatures dropping to 2°C (37°F) and daytime highs reaching 27°C (82°F), averaging around 15°C (59°F). The precipitation in March is considerably lighter at 142 mm (5.6 inches) over just 20 days and the humidity is much lower at 38%. For a more detailed view of March weather specifically, check out Ilam weather in March.
In comparing the weather of September and April, it's evident that September is significantly warmer and more humid. September boasts average temperatures ranging from a mild 21°C (71°F) to a maximum of 29°C (85°F), while April sees cooler averages, with temperatures spanning from a minimum of 8°C (46°F) to a maximum of 28°C (82°F). Additionally, September experiences much higher precipitation levels, with 375 mm (14.8 in) falling over 28 days, compared to April's 210 mm (8.3 in) over just 24 days. Moreover, the humidity in September is markedly high at 93%, while April's humidity is considerably lower at 34%. For a closer look at how April weather specifically affects the region, visit Ilam weather in April.
In comparing the weather of September and May, September tends to be warmer, with average temperatures reaching 21°C (71°F) compared to May's average of 20°C (68°F). Both months share a maximum temperature of 29°C (85°F in September and 84°F in May), but September experiences higher humidity at 93%, making it feel more tropical than May’s more comfortable 60%. Additionally, September sees significantly more rainfall, accumulating 375 mm (14.8 in) over 28 days compared to May's 299 mm (11.8 in) across 29 days. For a detailed look at May weather in Ilam, you can visit Ilam weather in May.
When comparing the weather in September and June, we notice some similarities and differences. Both months experience a minimum temperature of around 16°C (61-62°F) and a maximum temperature reaching up to 29°C (84-85°F), with average temperatures slightly higher in June at 22°C (72°F) compared to September's 21°C (71°F). However, June has more significant rainfall, with total precipitation of 511 mm (20.1 in) over 29 days, while September experiences 375 mm (14.8 in) of rain across 28 days. Additionally, the humidity is higher in September at 93%, compared to June's 83%. For a more detailed look at the weather in June, you can visit Ilam weather in June.
In comparing the weather between September and July, we find some notable differences. September typically sees temperatures ranging from a minimum of 16°C (62°F) to a maximum of 29°C (85°F), with an average temperature of 21°C (71°F). In contrast, July is slightly warmer, with minimum temperatures around 19°C (66°F) and a maximum of 30°C (85°F), giving it an average of 22°C (72°F). While both months experience high humidity levels of 93%, July is significantly wetter, with precipitation reaching 940 mm (37.0 in) over 30 days, compared to September's 375 mm (14.8 in) over 28 days. For more specific weather patterns, you can check Ilam weather in July.
In comparing the weather patterns between August and September, we see a slight decrease in temperature as the minimums drop from 19°C (66°F) in August to 16°C (62°F) in September, while the average temperature also decreases from 22°C (73°F) to 21°C (71°F). August boasts a slightly higher maximum temperature of 30°C (86°F) compared to September's peak of 29°C (85°F). Rainfall is notably more pronounced in August, with 605 mm (23.8 in) reported over 31 days, whereas September sees a significant reduction in precipitation to 375 mm (14.8 in) across 28 days. Despite the decrease in temperature and precipitation, both months maintain a high humidity level of 93%. For a closer look at August weather specifics, you can check Ilam weather in August.
In comparing the weather between September and October, we see a notable shift in temperature and precipitation. September boasts a warmer climate with average temperatures around 21°C (71°F) and maximums reaching up to 29°C (85°F), while October sees a decrease in nighttime lows to 9°C (48°F) and an average of 19°C (66°F). Additionally, September is much wetter, receiving 375 mm (14.8 in) of rainfall over 28 days, compared to October's 180 mm (7.1 in) distributed over 20 days. Humidity levels also drop slightly from a high of 93% in September to 88% in October, suggesting a gradual shift towards drier conditions. For more detailed information about the weather in October, you can visit Ilam weather in October.
September and November present strikingly different weather patterns. September is notably warmer, with temperatures ranging from a minimum of 16°C (62°F) to a maximum of 29°C (85°F) and an average of 21°C (71°F). The month also experiences high humidity at 93% and significant rainfall, totaling 375 mm (14.8 in) over 28 days. In contrast, November brings cooler temperatures, with a minimum of 5°C (42°F) and a maximum of 26°C (79°F), averaging around 14°C (58°F). The precipitation drops dramatically to just 19 mm (0.8 in) over 5 days, and humidity decreases to 80%. These contrasts highlight the transitional shift from the rainy season in September to the drier, cooler climate of November. For more details, you can check Ilam weather in November.
September and December present a striking contrast in weather conditions. September boasts milder temperatures, with averages around 21°C (71°F) but can soar to a high of 29°C (85°F), coupled with significant rainfall of 375 mm (14.8 in) over 28 days, resulting in a high humidity level of 93%. In contrast, December experiences much cooler weather, with an average temperature of 11°C (51°F) and a maximum of 22°C (72°F). Rainfall is minimal, totaling just 18 mm (0.7 in) across only 3 days, and humidity drops to a more comfortable 75%. For more details, you can check Ilam weather in December.
September in Ilam presents a unique blend of warmth and moisture, distinguishing it from the drier months that precede it. With temperatures reaching a maximum of 29°C, residents and visitors alike experience mild days, punctuated by cooler evenings. However, the lush landscape is fueled by significant rainfall, as September witnesses the highest precipitation of the year, averaging 375 mm across nearly every day of the month. This lush, humid environment, characterized by a staggering 93% humidity, sets September apart in the region’s climate, making it a vibrant, if somewhat soggy, time to experience Ilam’s natural beauty. For a deeper understanding of the weather patterns throughout the year, visit Ilam Climate.